The document analyzes morphological and compositional data of the central peak of Tycho crater on the Moon. Analysis of high-resolution Chandrayaan-1 and LRO data reveals evidence of volcanic features on the central peak, including volcanic vents, lava ponds showing cooling cracks, lava flows, and domes. Compositionally, M3 data show the central peak is heterogeneous and dominated by high-Ca pyroxene-rich rocks, with an anorthositic base. These morphological and mineralogical features suggest the central peak underwent multiple modifications after impact, exposing deep lunar crustal materials through volcanism triggered by the impact event.
International Refereed Journal of Engineering and Science (IRJES)irjes
a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
The GRAIL spacecraft measured the gravity field of the Moon at high resolution, allowing determination of the bulk density and porosity of the lunar crust. The analysis found:
1) The bulk density of the lunar highlands crust is 2550 kg/m3, substantially lower than previous estimates due to impact-induced porosity.
2) The average porosity of the crust is 12%, varying regionally from 4-21% and correlated with impact basins.
3) A new global crustal thickness model was constructed satisfying seismic constraints with an average thickness of 34-43 km, indicating the Moon's composition is not highly enriched compared to Earth.
Jupiter’s magnetosphere and aurorae observed by the Juno spacecraft during it...Sérgio Sacani
The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral
emissions from a vantage point above the poles. Juno’s capture orbit spanned the jovian
magnetosphere from bow shock to the planet, providing magnetic field, charged particle,
and wave phenomena context for Juno’s passage over the poles and traverse of Jupiter’s
hazardous inner radiation belts. Juno’s energetic particle and plasma detectors measured
electrons precipitating in the polar regions, exciting intense aurorae, observed
simultaneously by the ultraviolet and infrared imaging spectrographs. Juno transited
beneath the most intense parts of the radiation belts, passed about 4000 kilometers
above the cloud tops at closest approach, well inside the jovian rings, and recorded the
electrical signatures of high-velocity impacts with small particles as it traversed the equator.
Jupiter’s interior and deep atmosphere: The initial pole-to-pole passes with ...Sérgio Sacani
On 27 August 2016, the Juno spacecraft acquired science observations of Jupiter,
passing less than 5000 kilometers above the equatorial cloud tops. Images of Jupiter’s
poles show a chaotic scene, unlike Saturn’s poles. Microwave sounding reveals weather
features at pressures deeper than 100 bars, dominated by an ammonia-rich, narrow
low-latitude plume resembling a deeper, wider version of Earth’s Hadley cell. Near-infrared
mapping reveals the relative humidity within prominent downwelling regions. Juno’s
measured gravity field differs substantially from the last available estimate and is one
order of magnitude more precise. This has implications for the distribution of heavy
elements in the interior, including the existence and mass of Jupiter’s core. The observed
magnetic field exhibits smaller spatial variations than expected, indicative of a rich
harmonic content.
A rocky planet_transiting_a_nearby_low_mass_starSérgio Sacani
Um exoplaneta rochoso do tamanho da Terra, orbita uma estrela pequena e próxima, poderia ser o mundo mais importante já encontrado além do Sistema Solar, disseram os astrônomos.
O planeta localiza-se na constelação de Vela, no hemisfério sul do céu e é próximo o suficiente para que os telescópios possam observar qualquer atmosfera que ele possua, um procedimento que poderia ajudar a registrar algum tipo de vida, se ela existisse em outros planetas, no futuro.
Denominado de GJ 1132b, o exoplaneta é cerca de 16% maior que a Terra, e está localizado a cerca de 39 anos-luz de distância, o que faz com que ele seja três vezes mais próximo da Terra do que qualquer outro exoplaneta rochoso já descoberto. Nessa distância, espera-se que os telescópios sejam capazes de fazer uma análise química de sua atmosfera, a velocidade dos seus ventos e as cores do pôr-do-Sol, que acontecem no exoplaneta.
Os astrônomos registraram o planeta à medida que ele passava na frente da sua estrela, uma estrela do tipo anã vermelha, com somente um quinto do tamanho do Sol. Apesar de muito mais fria e muito mais apagada que o Sol, o GJ 1132b, tem uma órbita tão próxima da estrela que as suas temperaturas superficiais atingem cerca de 260 graus Celsius.
Essa temperatura, obviamente, é muito alta para reter a água em estado líquido na superfície do exoplaneta, fazendo com que ele seja inóspito para a vida, mas não tão quente para queimar toda uma atmosfera que pode ter se formado no planeta.
The document summarizes the first observations of the magnetic Kelvin-Helmholtz instability in the solar corona using high-resolution imaging from NASA's Solar Dynamics Observatory. The instability was detected on the northern flank of a fast coronal mass ejection, appearing as substructures or waves against the darker coronal background. Analysis found the observed phase speed of the waves to be about half the speed of the ejecta front, validating theories of the non-linear dynamics of this instability in magnetized plasma environments. The findings provide new insights into fundamental plasma processes in the solar atmosphere and solar-terrestrial system.
The x-ray diffraction analysis of soil samples from Rocknest at Gale Crater on Mars revealed:
1) Crystalline components including plagioclase, olivine, augite, pigeonite, and minor amounts of other phases.
2) 27±14% of the soil was amorphous material, likely containing multiple iron-bearing and volatile phases including possibly hisingerite.
3) The crystalline components are similar to martian basalts and meteorites, while the amorphous component is similar to soils on Earth like those on Mauna Kea, Hawaii.
International Refereed Journal of Engineering and Science (IRJES)irjes
a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
The GRAIL spacecraft measured the gravity field of the Moon at high resolution, allowing determination of the bulk density and porosity of the lunar crust. The analysis found:
1) The bulk density of the lunar highlands crust is 2550 kg/m3, substantially lower than previous estimates due to impact-induced porosity.
2) The average porosity of the crust is 12%, varying regionally from 4-21% and correlated with impact basins.
3) A new global crustal thickness model was constructed satisfying seismic constraints with an average thickness of 34-43 km, indicating the Moon's composition is not highly enriched compared to Earth.
Jupiter’s magnetosphere and aurorae observed by the Juno spacecraft during it...Sérgio Sacani
The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral
emissions from a vantage point above the poles. Juno’s capture orbit spanned the jovian
magnetosphere from bow shock to the planet, providing magnetic field, charged particle,
and wave phenomena context for Juno’s passage over the poles and traverse of Jupiter’s
hazardous inner radiation belts. Juno’s energetic particle and plasma detectors measured
electrons precipitating in the polar regions, exciting intense aurorae, observed
simultaneously by the ultraviolet and infrared imaging spectrographs. Juno transited
beneath the most intense parts of the radiation belts, passed about 4000 kilometers
above the cloud tops at closest approach, well inside the jovian rings, and recorded the
electrical signatures of high-velocity impacts with small particles as it traversed the equator.
Jupiter’s interior and deep atmosphere: The initial pole-to-pole passes with ...Sérgio Sacani
On 27 August 2016, the Juno spacecraft acquired science observations of Jupiter,
passing less than 5000 kilometers above the equatorial cloud tops. Images of Jupiter’s
poles show a chaotic scene, unlike Saturn’s poles. Microwave sounding reveals weather
features at pressures deeper than 100 bars, dominated by an ammonia-rich, narrow
low-latitude plume resembling a deeper, wider version of Earth’s Hadley cell. Near-infrared
mapping reveals the relative humidity within prominent downwelling regions. Juno’s
measured gravity field differs substantially from the last available estimate and is one
order of magnitude more precise. This has implications for the distribution of heavy
elements in the interior, including the existence and mass of Jupiter’s core. The observed
magnetic field exhibits smaller spatial variations than expected, indicative of a rich
harmonic content.
A rocky planet_transiting_a_nearby_low_mass_starSérgio Sacani
Um exoplaneta rochoso do tamanho da Terra, orbita uma estrela pequena e próxima, poderia ser o mundo mais importante já encontrado além do Sistema Solar, disseram os astrônomos.
O planeta localiza-se na constelação de Vela, no hemisfério sul do céu e é próximo o suficiente para que os telescópios possam observar qualquer atmosfera que ele possua, um procedimento que poderia ajudar a registrar algum tipo de vida, se ela existisse em outros planetas, no futuro.
Denominado de GJ 1132b, o exoplaneta é cerca de 16% maior que a Terra, e está localizado a cerca de 39 anos-luz de distância, o que faz com que ele seja três vezes mais próximo da Terra do que qualquer outro exoplaneta rochoso já descoberto. Nessa distância, espera-se que os telescópios sejam capazes de fazer uma análise química de sua atmosfera, a velocidade dos seus ventos e as cores do pôr-do-Sol, que acontecem no exoplaneta.
Os astrônomos registraram o planeta à medida que ele passava na frente da sua estrela, uma estrela do tipo anã vermelha, com somente um quinto do tamanho do Sol. Apesar de muito mais fria e muito mais apagada que o Sol, o GJ 1132b, tem uma órbita tão próxima da estrela que as suas temperaturas superficiais atingem cerca de 260 graus Celsius.
Essa temperatura, obviamente, é muito alta para reter a água em estado líquido na superfície do exoplaneta, fazendo com que ele seja inóspito para a vida, mas não tão quente para queimar toda uma atmosfera que pode ter se formado no planeta.
The document summarizes the first observations of the magnetic Kelvin-Helmholtz instability in the solar corona using high-resolution imaging from NASA's Solar Dynamics Observatory. The instability was detected on the northern flank of a fast coronal mass ejection, appearing as substructures or waves against the darker coronal background. Analysis found the observed phase speed of the waves to be about half the speed of the ejecta front, validating theories of the non-linear dynamics of this instability in magnetized plasma environments. The findings provide new insights into fundamental plasma processes in the solar atmosphere and solar-terrestrial system.
The x-ray diffraction analysis of soil samples from Rocknest at Gale Crater on Mars revealed:
1) Crystalline components including plagioclase, olivine, augite, pigeonite, and minor amounts of other phases.
2) 27±14% of the soil was amorphous material, likely containing multiple iron-bearing and volatile phases including possibly hisingerite.
3) The crystalline components are similar to martian basalts and meteorites, while the amorphous component is similar to soils on Earth like those on Mauna Kea, Hawaii.
1. The document analyzes the spatial distribution and size-frequency of rayed impact craters on the Moon using Clementine image data.
2. It finds that the size-frequency distribution of rayed craters indicates an average surface age of 750 million years, with compositional rays potentially persisting longer.
3. Small craters below 5 km in diameter show evidence of faster fading of ejecta rays, with an average retention time of only about 5 million years for craters 1-500m in size.
1) The Titan Mare Explorer (TiME) mission aims to be the first exploration of an extra-terrestrial sea by sending a lander to study Ligeia Mare on Titan.
2) TiME will directly measure the organic constituents in Titan's seas to better understand Titan's methane cycle and look for patterns in chemical abundances. It will also determine sea depths, constrain lacustrine processes, and analyze meteorology over the seas.
3) If selected, TiME is proposed as a Discovery-class mission and would launch in 2015, arriving at Titan in 2022 to spend 3 months studying Ligeia Mare using instruments like a mass spectrometer and sonar to achieve its science objectives.
This document summarizes observations of the exoplanet HD 189733b taken with Chandra and XMM-Newton telescopes. The observations detected X-ray emissions from both the planet-hosting star HD 189733A and its companion star HD 189733B. A transit of HD 189733b in front of its star was detected in soft X-rays, with a transit depth of 6-8% compared to 2.41% in the optical. This is interpreted as evidence for an extended atmosphere around the planet that is opaque to X-rays but transparent at optical wavelengths. The magnetic activity of the companion star HD 189733B was also found to be inconsistent with the activity of the planet-hosting star, possibly due to
Preliminary Studies of the Litho-Structural Evolution of Areas Around Obudu N...IJRESJOURNAL
ABSTRACT: Rocks underlying the northeastern sector of Obudu area forms part of the Bamenda massif which is a westward extension of the Precambrian terrains of Cameroon into southeastern Nigeria. These rocks are frequently found in the basement complex of Nigeria and include the migmatitic gneiss as the early metamorphic tectonites constituting over 60% of the outcropping rocks in the study area. The basement rock of the study area comprised of the migmatite gneiss and biotite-hornblende garnetiferous gneiss as well as the porphyroblastic gneiss and granite gneiss which formed the basement intruded by the Older granites (Pan-African granitoids). The Older granites in this area include charnockite, porphyritic granite, medium grained granite, diorite and pegmatite/aplite with relatively undeformed veins of dolerite and quartz. The presence of garnet nodules in the biotite-hornblende gneiss indicates high grade tectono-thermal metamorphism of a possible sedimentary protholith. The shearing observed in some rock outcrops are indication that there have been a series of structural deformation alongside magmatism and metamorphism in the area.
The proposed VELOCITÉ mission aims to study geological activity and interior structure on Venus through a combination of orbital and lander-based instruments over a 5-year period. The orbital component, called VISAGE, would carry an interferometric synthetic aperture radar, ground penetrating radar, and high-precision gravity instruments to characterize surface topography, subsurface structure, and gravity field variations. Two landers, called LOVE 1 & 2, would conduct in-situ seismic and permittivity measurements to study near-surface structure. The mission aims to improve understanding of Venusian tectonics, volcanism, and interior dynamics.
Curiosity at gale_crater_characterization_and_analysis_of_the_rocknest_sand_s...Sérgio Sacani
The Rocknest sand shadow analyzed by the Curiosity rover on Mars was similar to coarse-grained ripples analyzed by previous rovers. It consisted of an upper layer of very coarse sand grains armoring the surface, underlain by finer grains. Analysis found the sand was around 55% crystalline material of basaltic composition and 45% amorphous iron-rich glass. This amorphous component contained the volatiles detected and was similar to soils analyzed at other Mars sites, implying the materials were locally derived from similar basaltic sources globally on Mars.
This document summarizes a study of the Corona Australis star-forming region using data from the Herschel space telescope. Key findings include:
1) Herschel maps reveal many cluster members, including some embedded very low-mass objects, several protostars (some extended), and substantial emission from the surrounding cloud.
2) Striking structures are seen, such as bright filaments around the IRS 5 protostar complex and a bubble-shaped rim associated with the Class I object IRS 2.
3) Disks around Class II objects show a wide range of properties, from massive primordial disks to disks with substantial dust depletion or evidence of inside-out evolution. This indicates a diversity of disk evolution
The petrochemistry of_jake_m_a_martian_mugeariteSérgio Sacani
The rock "Jake_M" was the first rock analyzed by Curiosity on Mars. It has a distinct chemical composition compared to other known Martian rocks. Jake_M has a basaltic composition but is alkaline, with over 15% normative nepheline content. Its chemical makeup is similar to terrestrial mugearites, fractionated alkaline rocks found at ocean islands and rifts. This suggests Jake_M formed through extensive fractional crystallization of an alkaline magma at elevated pressure, possibly with water. The discovery of an alkaline rock expands the diversity of known Martian igneous compositions.
The Solar System consists of the Sun and objects bound to it by gravity, including 8 planets. The 4 inner terrestrial planets - Mercury, Venus, Earth, and Mars - are primarily rocky. The 4 outer gas giants - Jupiter, Saturn, Uranus, and Neptune - are massive and gaseous. Between Mars and Jupiter is the asteroid belt. Comets originate from the Kuiper belt beyond Neptune and have highly elliptical orbits. Each planet has unique characteristics such as atmospheric composition, rotation period, and presence of moons and rings.
An Integrated Study of Gravity and Magnetic Data to Determine Subsurface Stru...iosrjce
:The present study wascarried out to delineate the location, extension, trend and depth of subsurface
structures of Alamein area. To achieve this aim, the gravity and aeromagnetic data have been subjected to
different analytical techniques. The Fast Fourier Transform technique was used to separatethe residual
components from the regional ones. The resulted maps showed that the area was affected mainly bytheENE, EW,
WNWand NWtectonic trends. In addition, spectral analysis technique was applied on magnetic anomalies to
estimate the depth to basement surface, which varies from 3.03 in southern part to 7.24 Km in northern part.3DEulerdeconvloution
and tilt angle derivative techniques were carried out to detect the edges of magnetic sources
and to determine their depths.Correlation between them shows acoincidence between Euler solution and zero
lines of tilt angle map. A tentative basement structure map is constructed from the integration of these results
and geological information. This map shows alternative uplifted and downfaulted structure trending in the ENE,
NE and E-W directions. In addition, the NNW to NW strike-slip faults intersected them in later events. Finally,
2-D modeling technique was run on three gravity and magnetic profiles in the same location. Different drilled
wells and the constructed basement structure map support these modeled profiles. Theyshow an acidic basement
rocks. A general decreasing of Conrad discontinuity depths from about 20.5 km at southern part to 17.9 km at
northern part can be noticed. Moreover, the crustal thickness (depth to Moho discontinuity), varies between
31.5 and 28.5 km revealing visibly crustal stretching and thinning northerly
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Extensive Noachian fluvial systems in Arabia Terra: Implications for early Ma...Sérgio Sacani
Valley networks are some of the strongest lines of evidence for
extensive fluvial activity on early (Noachian; >3.7 Ga) Mars. However,
their purported absence on certain ancient terrains, such as
Arabia Terra, is at variance with patterns of precipitation as predicted
by “warm and wet” climate models. This disagreement has contributed
to the development of an alternative “icy highlands” scenario,
whereby valley networks were formed by the melting of highland ice
sheets. Here, we show through regional mapping that Arabia Terra
shows evidence for extensive networks of sinuous ridges. We interpret
these ridge features as inverted fluvial channels that formed in
the Noachian, before being subject to burial and exhumation. The
inverted channels developed on extensive aggrading flood plains. As
the inverted channels are both sourced in, and traverse across, Arabia
Terra, their formation is inconsistent with discrete, localized sources
of water, such as meltwater from highland ice sheets. Our results are
instead more consistent with an early Mars that supported widespread
precipitation and runoff.
The document provides an integrated geological study of the Santiago Basin in Peru based on seismic data, gravity data, well data, and field work. It finds that the basin has a complex structural style resulting from inversion of a Permian-Jurassic rift system, including thrust faults, wrench faults, and folded structures. Maturity modeling indicates three source rock formations - the Pozo Shale, Upper Chonta Formation, and Pucara Formation - have generated oil in the basin. The basin has significant hydrocarbon potential evidenced by over 20 oil seeps.
An Earth-mass planet orbiting a Centauri BCarlos Bella
1) Researchers detected an Earth-mass planet orbiting the star Alpha Centauri B.
2) The planet has a minimum mass similar to Earth and orbits its star with a period of 3.236 days, within 0.04 astronomical units.
3) This makes it the lightest planet detected orbiting a Sun-like star and the closest exoplanet to our solar system found to date.
This document summarizes the discovery of an Earth-mass planet orbiting the star Alpha Centauri B. The planet, with a minimum mass similar to Earth, has an orbital period of 3.236 days and is located about 0.04 astronomical units from the star. High-precision radial velocity measurements from the HARPS spectrograph revealed the planet's signal, making it the lightest planet detected around a solar-type star. The discovery demonstrates that current techniques can detect potentially habitable super-Earth planets around Sun-like stars and habitable Earth-like planets around cooler stars.
This document introduces the VLT-FLAMES Tarantula Survey, which obtained multi-epoch optical spectroscopy of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud. The survey aims to detect massive binary systems through variations in radial velocities and to characterize the properties of O- and B-type stars, addressing questions about stellar and cluster evolution. Spectral classifications are provided for newly discovered emission-line stars, including a new Wolf-Rayet star. The survey data and reduction procedures are overviewed, and upcoming analyses of the massive star properties are announced.
The document summarizes information about the Lagoon Nebula and its surrounding regions. It is located in the Sagittarius-Carina Arm of the Milky Way, about 1.3 kpc away. The Lagoon Nebula contains the young open cluster NGC 6530 (1-3 Myr old), which has several O and B type stars. Younger star formation is ongoing in regions like the Hourglass Nebula and M8 E. The complex structure of the region has been shaped by interactions between massive stars and molecular gas over multiple episodes of star formation.
The ChemCam instrument on the Curiosity rover identified two main soil types on Mars - a fine-grained mafic soil and a coarse-grained felsic soil locally derived. The mafic soil is similar to widespread martian soils and dust, and possesses a ubiquitous hydrogen signature from hydrated amorphous phases. This hydration may account for a significant fraction of hydrogen detected globally on Mars. ChemCam analyses did not reveal water vapor exchange between the soil and atmosphere. The observations provide constraints on the nature and hydration of amorphous phases in the soil.
Using receiver function analysis of seismic data recorded by 45 broadband seismometers on Streymoy Island, Faroe Islands, we estimate:
1) The depth of the converting boundary beneath the Faroe Islands is between 29-32 km, which represents conversion from a region of high-velocity lower crust rather than the crust-mantle boundary.
2) Forward modeling suggests this high-velocity lower crust is at least 6 km thick.
3) The thick high-velocity lower crust is interpreted to result from intrusion of magma into the pre-existing continental crust during continental breakup, rather than underplating of igneous material at the base of the crust.
TECTONIC FRAMEWORK OF EAST GABAL NUQRA AREA, SOUTH EASTERN DESERT, EGYPTDr. Ibr@him
The document describes a ring dyke complex located east of Gabal Nuqra in Egypt. Three magmatic events formed the rocks in the area: 1) Granites associated with the Nubian sandstone basin formation. 2) Volcanic ring dykes post-dating the basin. 3) A trachy-basaltic flow related to Red Sea rifting. Structural analysis identified three tectonic events: 1) NE-SW extension formed the Nubian basin. 2) NW-SE extension reactivated pre-existing faults. 3) E-W to ENE-WSW faults localized ring dyke emplacement and configured the trachy-basaltic flow. Hydrothermal activity
The document summarizes observations of volcanic features associated with the lunar craters Tycho and Aristarchus. It finds that Tycho contains more viscous lava flows with higher albedos, indicating compositional differences from Aristarchus. "Lakes" on the crater rims are thought to consist of lava from vents. The crater floors likely contain lava that drained into subsurface chambers. Late eruptions at Aristarchus obscured floor details. Widespread deposits around the craters resulted from base surges, indicating large explosions formed the craters. Counts of impact craters on volcanic features date them at different times, with Aristarchus about 1.6 times older than Tycho, though the floors are roughly the same age.
The two largest impact basins recently discovered at Vesta's south pole are Rheasilvia and Veneneia. Rheasilvia is ~500 km wide and 19 km deep, making it one of the largest impact features on Vesta. It has a central massif and spiral ridge patterns on its floor. Veneneia is an older, partially buried ~400 km basin located beneath Rheasilvia. Crater counts date both basins to 1-2 billion years old, indicating major geological resetting of Vesta occurred relatively recently.
1. The document analyzes the spatial distribution and size-frequency of rayed impact craters on the Moon using Clementine image data.
2. It finds that the size-frequency distribution of rayed craters indicates an average surface age of 750 million years, with compositional rays potentially persisting longer.
3. Small craters below 5 km in diameter show evidence of faster fading of ejecta rays, with an average retention time of only about 5 million years for craters 1-500m in size.
1) The Titan Mare Explorer (TiME) mission aims to be the first exploration of an extra-terrestrial sea by sending a lander to study Ligeia Mare on Titan.
2) TiME will directly measure the organic constituents in Titan's seas to better understand Titan's methane cycle and look for patterns in chemical abundances. It will also determine sea depths, constrain lacustrine processes, and analyze meteorology over the seas.
3) If selected, TiME is proposed as a Discovery-class mission and would launch in 2015, arriving at Titan in 2022 to spend 3 months studying Ligeia Mare using instruments like a mass spectrometer and sonar to achieve its science objectives.
This document summarizes observations of the exoplanet HD 189733b taken with Chandra and XMM-Newton telescopes. The observations detected X-ray emissions from both the planet-hosting star HD 189733A and its companion star HD 189733B. A transit of HD 189733b in front of its star was detected in soft X-rays, with a transit depth of 6-8% compared to 2.41% in the optical. This is interpreted as evidence for an extended atmosphere around the planet that is opaque to X-rays but transparent at optical wavelengths. The magnetic activity of the companion star HD 189733B was also found to be inconsistent with the activity of the planet-hosting star, possibly due to
Preliminary Studies of the Litho-Structural Evolution of Areas Around Obudu N...IJRESJOURNAL
ABSTRACT: Rocks underlying the northeastern sector of Obudu area forms part of the Bamenda massif which is a westward extension of the Precambrian terrains of Cameroon into southeastern Nigeria. These rocks are frequently found in the basement complex of Nigeria and include the migmatitic gneiss as the early metamorphic tectonites constituting over 60% of the outcropping rocks in the study area. The basement rock of the study area comprised of the migmatite gneiss and biotite-hornblende garnetiferous gneiss as well as the porphyroblastic gneiss and granite gneiss which formed the basement intruded by the Older granites (Pan-African granitoids). The Older granites in this area include charnockite, porphyritic granite, medium grained granite, diorite and pegmatite/aplite with relatively undeformed veins of dolerite and quartz. The presence of garnet nodules in the biotite-hornblende gneiss indicates high grade tectono-thermal metamorphism of a possible sedimentary protholith. The shearing observed in some rock outcrops are indication that there have been a series of structural deformation alongside magmatism and metamorphism in the area.
The proposed VELOCITÉ mission aims to study geological activity and interior structure on Venus through a combination of orbital and lander-based instruments over a 5-year period. The orbital component, called VISAGE, would carry an interferometric synthetic aperture radar, ground penetrating radar, and high-precision gravity instruments to characterize surface topography, subsurface structure, and gravity field variations. Two landers, called LOVE 1 & 2, would conduct in-situ seismic and permittivity measurements to study near-surface structure. The mission aims to improve understanding of Venusian tectonics, volcanism, and interior dynamics.
Curiosity at gale_crater_characterization_and_analysis_of_the_rocknest_sand_s...Sérgio Sacani
The Rocknest sand shadow analyzed by the Curiosity rover on Mars was similar to coarse-grained ripples analyzed by previous rovers. It consisted of an upper layer of very coarse sand grains armoring the surface, underlain by finer grains. Analysis found the sand was around 55% crystalline material of basaltic composition and 45% amorphous iron-rich glass. This amorphous component contained the volatiles detected and was similar to soils analyzed at other Mars sites, implying the materials were locally derived from similar basaltic sources globally on Mars.
This document summarizes a study of the Corona Australis star-forming region using data from the Herschel space telescope. Key findings include:
1) Herschel maps reveal many cluster members, including some embedded very low-mass objects, several protostars (some extended), and substantial emission from the surrounding cloud.
2) Striking structures are seen, such as bright filaments around the IRS 5 protostar complex and a bubble-shaped rim associated with the Class I object IRS 2.
3) Disks around Class II objects show a wide range of properties, from massive primordial disks to disks with substantial dust depletion or evidence of inside-out evolution. This indicates a diversity of disk evolution
The petrochemistry of_jake_m_a_martian_mugeariteSérgio Sacani
The rock "Jake_M" was the first rock analyzed by Curiosity on Mars. It has a distinct chemical composition compared to other known Martian rocks. Jake_M has a basaltic composition but is alkaline, with over 15% normative nepheline content. Its chemical makeup is similar to terrestrial mugearites, fractionated alkaline rocks found at ocean islands and rifts. This suggests Jake_M formed through extensive fractional crystallization of an alkaline magma at elevated pressure, possibly with water. The discovery of an alkaline rock expands the diversity of known Martian igneous compositions.
The Solar System consists of the Sun and objects bound to it by gravity, including 8 planets. The 4 inner terrestrial planets - Mercury, Venus, Earth, and Mars - are primarily rocky. The 4 outer gas giants - Jupiter, Saturn, Uranus, and Neptune - are massive and gaseous. Between Mars and Jupiter is the asteroid belt. Comets originate from the Kuiper belt beyond Neptune and have highly elliptical orbits. Each planet has unique characteristics such as atmospheric composition, rotation period, and presence of moons and rings.
An Integrated Study of Gravity and Magnetic Data to Determine Subsurface Stru...iosrjce
:The present study wascarried out to delineate the location, extension, trend and depth of subsurface
structures of Alamein area. To achieve this aim, the gravity and aeromagnetic data have been subjected to
different analytical techniques. The Fast Fourier Transform technique was used to separatethe residual
components from the regional ones. The resulted maps showed that the area was affected mainly bytheENE, EW,
WNWand NWtectonic trends. In addition, spectral analysis technique was applied on magnetic anomalies to
estimate the depth to basement surface, which varies from 3.03 in southern part to 7.24 Km in northern part.3DEulerdeconvloution
and tilt angle derivative techniques were carried out to detect the edges of magnetic sources
and to determine their depths.Correlation between them shows acoincidence between Euler solution and zero
lines of tilt angle map. A tentative basement structure map is constructed from the integration of these results
and geological information. This map shows alternative uplifted and downfaulted structure trending in the ENE,
NE and E-W directions. In addition, the NNW to NW strike-slip faults intersected them in later events. Finally,
2-D modeling technique was run on three gravity and magnetic profiles in the same location. Different drilled
wells and the constructed basement structure map support these modeled profiles. Theyshow an acidic basement
rocks. A general decreasing of Conrad discontinuity depths from about 20.5 km at southern part to 17.9 km at
northern part can be noticed. Moreover, the crustal thickness (depth to Moho discontinuity), varies between
31.5 and 28.5 km revealing visibly crustal stretching and thinning northerly
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Extensive Noachian fluvial systems in Arabia Terra: Implications for early Ma...Sérgio Sacani
Valley networks are some of the strongest lines of evidence for
extensive fluvial activity on early (Noachian; >3.7 Ga) Mars. However,
their purported absence on certain ancient terrains, such as
Arabia Terra, is at variance with patterns of precipitation as predicted
by “warm and wet” climate models. This disagreement has contributed
to the development of an alternative “icy highlands” scenario,
whereby valley networks were formed by the melting of highland ice
sheets. Here, we show through regional mapping that Arabia Terra
shows evidence for extensive networks of sinuous ridges. We interpret
these ridge features as inverted fluvial channels that formed in
the Noachian, before being subject to burial and exhumation. The
inverted channels developed on extensive aggrading flood plains. As
the inverted channels are both sourced in, and traverse across, Arabia
Terra, their formation is inconsistent with discrete, localized sources
of water, such as meltwater from highland ice sheets. Our results are
instead more consistent with an early Mars that supported widespread
precipitation and runoff.
The document provides an integrated geological study of the Santiago Basin in Peru based on seismic data, gravity data, well data, and field work. It finds that the basin has a complex structural style resulting from inversion of a Permian-Jurassic rift system, including thrust faults, wrench faults, and folded structures. Maturity modeling indicates three source rock formations - the Pozo Shale, Upper Chonta Formation, and Pucara Formation - have generated oil in the basin. The basin has significant hydrocarbon potential evidenced by over 20 oil seeps.
An Earth-mass planet orbiting a Centauri BCarlos Bella
1) Researchers detected an Earth-mass planet orbiting the star Alpha Centauri B.
2) The planet has a minimum mass similar to Earth and orbits its star with a period of 3.236 days, within 0.04 astronomical units.
3) This makes it the lightest planet detected orbiting a Sun-like star and the closest exoplanet to our solar system found to date.
This document summarizes the discovery of an Earth-mass planet orbiting the star Alpha Centauri B. The planet, with a minimum mass similar to Earth, has an orbital period of 3.236 days and is located about 0.04 astronomical units from the star. High-precision radial velocity measurements from the HARPS spectrograph revealed the planet's signal, making it the lightest planet detected around a solar-type star. The discovery demonstrates that current techniques can detect potentially habitable super-Earth planets around Sun-like stars and habitable Earth-like planets around cooler stars.
This document introduces the VLT-FLAMES Tarantula Survey, which obtained multi-epoch optical spectroscopy of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud. The survey aims to detect massive binary systems through variations in radial velocities and to characterize the properties of O- and B-type stars, addressing questions about stellar and cluster evolution. Spectral classifications are provided for newly discovered emission-line stars, including a new Wolf-Rayet star. The survey data and reduction procedures are overviewed, and upcoming analyses of the massive star properties are announced.
The document summarizes information about the Lagoon Nebula and its surrounding regions. It is located in the Sagittarius-Carina Arm of the Milky Way, about 1.3 kpc away. The Lagoon Nebula contains the young open cluster NGC 6530 (1-3 Myr old), which has several O and B type stars. Younger star formation is ongoing in regions like the Hourglass Nebula and M8 E. The complex structure of the region has been shaped by interactions between massive stars and molecular gas over multiple episodes of star formation.
The ChemCam instrument on the Curiosity rover identified two main soil types on Mars - a fine-grained mafic soil and a coarse-grained felsic soil locally derived. The mafic soil is similar to widespread martian soils and dust, and possesses a ubiquitous hydrogen signature from hydrated amorphous phases. This hydration may account for a significant fraction of hydrogen detected globally on Mars. ChemCam analyses did not reveal water vapor exchange between the soil and atmosphere. The observations provide constraints on the nature and hydration of amorphous phases in the soil.
Using receiver function analysis of seismic data recorded by 45 broadband seismometers on Streymoy Island, Faroe Islands, we estimate:
1) The depth of the converting boundary beneath the Faroe Islands is between 29-32 km, which represents conversion from a region of high-velocity lower crust rather than the crust-mantle boundary.
2) Forward modeling suggests this high-velocity lower crust is at least 6 km thick.
3) The thick high-velocity lower crust is interpreted to result from intrusion of magma into the pre-existing continental crust during continental breakup, rather than underplating of igneous material at the base of the crust.
TECTONIC FRAMEWORK OF EAST GABAL NUQRA AREA, SOUTH EASTERN DESERT, EGYPTDr. Ibr@him
The document describes a ring dyke complex located east of Gabal Nuqra in Egypt. Three magmatic events formed the rocks in the area: 1) Granites associated with the Nubian sandstone basin formation. 2) Volcanic ring dykes post-dating the basin. 3) A trachy-basaltic flow related to Red Sea rifting. Structural analysis identified three tectonic events: 1) NE-SW extension formed the Nubian basin. 2) NW-SE extension reactivated pre-existing faults. 3) E-W to ENE-WSW faults localized ring dyke emplacement and configured the trachy-basaltic flow. Hydrothermal activity
The document summarizes observations of volcanic features associated with the lunar craters Tycho and Aristarchus. It finds that Tycho contains more viscous lava flows with higher albedos, indicating compositional differences from Aristarchus. "Lakes" on the crater rims are thought to consist of lava from vents. The crater floors likely contain lava that drained into subsurface chambers. Late eruptions at Aristarchus obscured floor details. Widespread deposits around the craters resulted from base surges, indicating large explosions formed the craters. Counts of impact craters on volcanic features date them at different times, with Aristarchus about 1.6 times older than Tycho, though the floors are roughly the same age.
The two largest impact basins recently discovered at Vesta's south pole are Rheasilvia and Veneneia. Rheasilvia is ~500 km wide and 19 km deep, making it one of the largest impact features on Vesta. It has a central massif and spiral ridge patterns on its floor. Veneneia is an older, partially buried ~400 km basin located beneath Rheasilvia. Crater counts date both basins to 1-2 billion years old, indicating major geological resetting of Vesta occurred relatively recently.
The structure of_irregular_galaxy_ngc3239Sérgio Sacani
This document appears to be a citation to a 1990 publication in the Publications of the Astronomical Society of the Pacific journal. However, without accessing the full text it is difficult to determine the key topics or essential information contained in the referenced publication based on the citation alone.
1) The growth of the first stars was halted by ultraviolet radiation feedback from the stars themselves.
2) Radiation from the protostar evaporated the circumstellar accretion disk when the star's mass reached 43 times the mass of the Sun.
3) These massive primordial stars may help explain the lack of pair-instability supernovae signatures in ancient metal-poor stars.
Mars methane detection_and_variability_at_gale_craterSérgio Sacani
The document appears to be from the journal Science and contains data from the Curiosity rover measuring methane levels on Mars over multiple dates ("sols") since its landing in 2012. Tables show measurements of methane taken at night and day with information on atmospheric conditions. Average methane levels were calculated for groupings of sols labeled "low methane" and "high methane", with the high methane group showing levels over 7 parts per billion by volume.
This document reports on observations of comet 103P/Hartley 2 made by the WISE space telescope in May 2010 and additional ground-based telescopes. The WISE observations detected the comet's coma, nucleus, and dust trail. Analysis of the coma suggests dust particles larger than those observed for comet 81P/Wild 2. The extracted nucleus is estimated to be 0.6 km in radius. Emission detected at 4.6 microns may be from carbon monoxide or carbon dioxide gas. Carbon dioxide production rates are estimated to be 3.5×1024 molecules per second. The dust trail was detected with an optical depth of 9×10-10 and minimum mass of 4×1010 kg. These observations provide
This very deep Chandra observation of the galaxy cluster Abell 2052 reveals detailed structure in the inner region, including bubbles evacuated by the radio lobes, compressed bubble rims, filaments, and loops. Two concentric shocks are seen, with a temperature rise measured for the inner shock. On larger scales, a spiral feature is detected, likely resulting from sloshing gas initiated by a previous merger. Initial evidence is also presented for previously unseen outer bubbles related to earlier black hole outbursts.
This document presents an analysis of metallicity gradients in the Milky Way disk as observed by the SEGUE survey. The key findings are:
1) The radial metallicity gradient (change in [Fe/H] with Galactic radius R) becomes flatter at heights above the plane (|Z|) greater than 1 kpc.
2) The median metallicity at large |Z| is consistent with outer disk open clusters, which also exhibit a flat radial gradient of [Fe/H] ∼ -0.5.
3) A flat metallicity gradient at high |Z| has implications for models of thick disk formation, as different formation scenarios predict different metallicity patterns in the thick disk.
The document summarizes the analysis of layered deposits inside the 174 km diameter Terby impact crater located on Mars. Stratigraphic and mineralogical analysis using multiple datasets suggests the deposits were formed subaqueously during the Noachian period. The thickest sequences display fan delta morphologies indicative of prograding/onlapping sedimentation over time. Phyllosilicates detected within layers support a sedimentary environment with sustained liquid water. Erosion during the Hesperian sculpted the current landforms, with later fluvial and then aeolian activity. Terby crater thus preserves a geologic record spanning multiple periods of Mars' history.
1) High resolution images of Tycho crater's central peak from Chandrayaan-1, LROC, and Kaguya datasets show evidence of late stage volcanic activity that modified the peak.
2) Two lava ponds were identified on the central peak using DTM and imagery. Imagery shows flow patterns, pyroclastics, and a volcanic vent associated with one of the ponds.
3) Spectral data indicates the lava ponds and crater floor have high-Ca pyroxene compositions, whereas the host rock is anorthositic, providing compositional evidence for the volcanic activity.
The document summarizes research on the origin of lunar concentric craters. The researchers analyzed data from Clementine, SELENE, and LRO to study 58 known concentric craters. They identified three morphological types and found concentric craters have shallower depths and smaller rim heights than fresh simple craters, suggesting impact degradation or uplift. Distribution near mare/highland boundaries and similarities to floor-fractured craters supports igneous intrusion as the most probable formation mechanism, rather than exogenic processes like simultaneous impacts or impact into layered targets.
This document summarizes the results of a deep near-infrared survey of the Carina Nebula complex using the HAWK-I instrument on the VLT. The survey imaged an area of 0.36 square degrees down to magnitudes of J=23, H=22, and Ks=21, detecting over 600,000 infrared sources. Color-magnitude diagrams of the sources were analyzed to determine properties of the low-mass stellar population such as ages and masses. The survey found that about 3200 sources have masses above 1 solar mass, consistent with expectations from the initial mass function. It also found that about half of the young stars in Carina are in a widely distributed, non-clustered configuration. Six
This document discusses predicting volcanic rock facies distributions in the Yingcheng Formation of the Yingshan depression based on seismic attributes. It uses coherence detection to identify craters, waveform clustering to predict facies boundaries, and amplitude attributes to refine boundaries and classify facies. Three main facies are identified - crater/proximal facies with good porosity, proximal facies with moderate porosity, and distal facies. Prediction results match well logging data and identify crater and distal facies as favorable reservoirs.
Magnetic field and_wind_of_kappa_ceti_towards_the_planetary_habitability_of_t...Sérgio Sacani
We report magnetic field measurements for κ
1 Cet, a proxy of the young Sun when life arose on Earth. We carry out an analysis
of the magnetic properties determined from spectropolarimetric observations and reconstruct its large-scale surface magnetic
field to derive the magnetic environment, stellar winds and particle flux permeating the interplanetary medium around κ
1 Cet.
Our results show a closer magnetosphere and mass-loss rate of M˙ = 9.7 × 10−13 M yr−1
, i.e., a factor 50 times larger than the
current solar wind mass-loss rate, resulting in a larger interaction via space weather disturbances between the stellar wind and
a hypothetical young-Earth analogue, potentially affecting the planet’s habitability. Interaction of the wind from the young Sun
with the planetary ancient magnetic field may have affected the young Earth and its life conditions.
The document provides a literature review on the geochemical analysis of volcanic tuffs. It summarizes several research papers that studied tuff samples from various locations using different analytical methods. The summaries describe the sample collection and preparation, analytical techniques used like XRD, SEM, isotope analysis, results of the chemical composition analysis, and conclusions about the tuff origins and evolution of the magma chambers. For example, one paper analyzed tuff samples from Chile and concluded they had a mafic composition indicating an underlying mafic magma chamber. Another paper studied tuffs in Colorado and found they had higher silica contents than surrounding rocks, suggesting depletion in mafic components.
A Morphological and Spatial Analysis of Volcanoes on VenusSérgio Sacani
Venus is home to many thousands of volcanic landforms that range in size from much less than 5 km to well over 100 km in diameter. Volcanism is clearly a major, widespread process on Venus, and is a principal expression of the planet's secular loss of interior heat. Without sufficient in situ data to clearly determine its internal structure, we can use the morphological and spatial properties of volcanoes across the planet to help place constraints on our understanding of the volcanic characteristics and history of Venus. With the Magellan synthetic-aperture radar full-resolution radar map left- and right-look global mosaics at 75 m-per-pixel resolution, we developed a global catalog of volcanoes on Venus that contains ∼85,000 edifices, ∼99% of which are <5 km in diameter. We find that Venus hosts far more volcanoes than previously mapped, and that although they are distributed across virtually the entire planet, size–frequency distribution analysis reveals a relative lack of edifices in the 20–100 km diameter range, which could be related to magma availability and eruption rate. Through spatial density analysis of volcanoes alongside assessments of geophysical data sets and proximal tectonic and volcanic structures, we report on the morphological and spatial patterns of volcanism on Venus to help gain new insights into the planet's geological evolution
Linne simple lunar mare crater geometry from lro observationsSérgio Sacani
This document analyzes the geometry of Linne crater on the Moon using high-resolution topographic data from LRO. The key findings are:
1) Linne's crater cavity is best described as a truncated cone, not a "bowl" as previously thought, with an inner wall slope of 33 degrees.
2) Linne's continuous ejecta blanket thickness decays with a power law exponent of -3.84, steeper than the typical -2.75 for craters on Earth.
3) When compared to other simple craters on the Moon, Mars, and Earth, Linne's normalized crater shape parameter suggests it represents an archetypal, well-preserved simple mare
Martian soil as revealed by ground-penetrating radar at the Tianwen-1 landing...Sérgio Sacani
Much of the Martian surface is covered by a weathering layer (regolith or soil) produced
by long-term surface processes such as impact gardening, eolian erosion, water weathering,
and glacial modifications. China’s first Martian mission, Tianwen-1, employed the Mars
Rover Penetrating Radar (RoPeR) to unveil the detailed structure of the regolith layer and
assess its loss tangent. The RoPeR radargram revealed the local regolith layer to be highly
heterogeneous and geologically complex and characterized by structures that resemble partial
or complete crater walls and near-surface impact lenses at a very shallow depth. However,
comparable radar data from the Lunar far side are rather uniform, despite the two surfaces
being geologically contemporary. The close-to-surface crater presented in this study shows
no detectable surface expression, which suggests an accelerated occultation rate for small
craters on the surface of Mars as compared to the rate on the Moon. This is probably due to
the relentless eolian processes on the Martian surface that led to the burial of the crater and
thus shielded it from further erosion. The high loss tangent indicates that the regolith at the
Tianwen-1 landing site is not dominated by water ice.
A Buried Volcano In The Calabrian Arc (Italy) Revealed By High-Resolution Aer...Andrea Porter
1. High-resolution aeromagnetic data revealed a previously unknown buried volcano in the Calabrian Arc of Italy.
2. The data showed a 20km long magnetized body extending from the seafloor to 3km below sea level.
3. The magnetic and geological evidence indicates this is the remnant plumbing system of a Pleistocene volcano that erupted, producing widespread tephra in the area.
This document summarizes evidence that argues against the hypothesis of a "lunar terminal cataclysm" approximately 3.9 billion years ago. It analyzes dating of lunar highland rocks and meteorites, finding they do not show a prominent peak at 3.9 billion years as expected, but rather a more uniform distribution of ages. Analysis of the cratering record of lunar basins also argues against a spike in the lunar bombardment rate at that time. Modeling of impact melt production and redistribution across the lunar surface further casts doubt on there having been a major cataclysm 3.9 billion years ago as hypothesized.
Modern water at low latitudes on Mars: Potential evidence from dune surfacesSérgio Sacani
Landforms on the Martian surface are critical to understanding the nature of surface processes in the recent
past. However, modern hydroclimatic conditions on Mars remain enigmatic, as explanations for the formation
of observed landforms are ambiguous. We report crusts, cracks, aggregates, and bright polygonal ridges on the
surfaces of hydrated salt-rich dunes of southern Utopia Planitia (~25°N) from in situ exploration by the Zhurong
rover. These surface features were inferred to form after 1.4 to 0.4 million years ago. Wind and CO2 frost processes can be ruled out as potential mechanisms. Instead, involvement of saline water from thawed frost/snow is
the most likely cause. This discovery sheds light on more humid conditions of the modern Martian climate and
provides critical clues to future exploration missions searching for signs of extant life, particularly at low latitudes with comparatively warmer, more amenable surface temperatures.
This document summarizes the results of a sub-mm survey of the Carina Nebula complex conducted with the LABOCA instrument on the APEX telescope. The survey mapped an area of 1.25° × 1.25° at 870 μm, revealing the morphology and distribution of cold dust clouds with masses down to a few solar masses. The total mass of clouds detected is estimated to be around 60,000 M☉. The cloud morphologies range from large clouds of several thousand solar masses to small diffuse clouds of only a few solar masses. The distribution of sub-mm emission generally agrees with Spitzer 8 μm maps, identifying clouds interacting with massive stars as well as infrared dark clouds. The survey provides crucial
The document discusses the provenance of Eocene sandstones in the southern Chindwin Basin of Myanmar. An integrated study of petrography, geochemistry, and detrital zircon dating of volcaniclastic sandstones from the late Middle Eocene Pondaung Formation reveals that the sandstones were derived from the erosion of an older calc-alkaline volcanic arc to the northeast. This volcanic arc had formed between 101-43 million years ago related to the subduction of the Neo-Tethys seafloor beneath the Eurasian continental margin. The erosion of this arc during the late Middle Eocene deposited volcaniclastic debris in the forearc basin of the Central Myanmar Basin, forming the Ponda
This document summarizes research on predicting volcanic rock fractures in the Yingcheng Formation in the Songliao Basin in China. Three methods were used to predict fractures: coherence analysis, ant colony algorithm, and curvature attributes applied to post-stack seismic data. Coherence identified low coherence zones indicating possible fractures. Ant colony algorithm clearly showed vertically oriented fractures trending NNE, NE, and NS. Curvature attributes identified zones of large curvature values coinciding with predicted fracture belts. Well data including FMI logs confirmed the fracture types and distributions matched the predictions. The methods effectively predicted the distribution of three fracture systems that are important for hydrocarbon exploration in the region.
This document presents the results of a study of 32 Bok globules, which are small, isolated molecular clouds that often contain young stellar objects. Millimeter and submillimeter continuum images were used to detect dust emission from star-forming cores within the globules. These data, along with infrared images and spectral energy distributions, were analyzed to determine the physical properties and evolutionary stages of the embedded sources. Submillimeter dust emission was detected in 26 globules, and the analysis identified 9 starless cores, 9 Class 0 protostars, and 12 Class I young stellar objects. The study found evidence that at least two-thirds of the globules studied were forming multiple stars within distances of 1,000-50,000 AU of each
The Richat Structure in Mauritania represents an eroded geologic dome comprised of sedimentary rocks from the late Proterozoic and Ordovician periods. While originally thought to be a meteorite impact structure, studies have found no evidence of shock processes. The structure likely formed from the uplift and erosion of an underlying alkaline magmatic body during the Cretaceous period. This research proposal aims to drill into the center of the structure to analyze rock compositions and better understand the subsurface geology and origin of the magmatic body through geophysical surveys and borehole data collection. Identifying the source and composition of the igneous rocks could help confirm or disprove the hypothesis of a subsurface intrusion related to continental ri
1) NWA 7034 is a 319.8g martian meteorite found in Morocco in 2011. It is a porous basaltic breccia composed of feldspar and pyroxene phenocrysts in a fine-grained groundmass containing magnetite.
2) Chemical and isotopic analyses indicate NWA 7034 formed on Mars 2.089 billion years ago from a geochemically enriched crustal source. It contains over 6000ppm water, more than most martian meteorites.
3) NWA 7034's composition is unlike SNC meteorites but matches basalts analyzed at Gusev Crater and the average martian crust measured by orbiters, providing the
Unique Meteorite from Early Amazonian Mars: Water-Rich Basaltic Breccia North...Carlos Bella
1) NWA 7034 is a 319.8g martian meteorite found in Morocco in 2011. It is a porous basaltic breccia composed of feldspar and pyroxene phenocrysts in a fine-grained groundmass.
2) Chemical and isotopic analyses indicate it formed on Mars 2.089 billion years ago from a magma enriched in the martian crust. It contains over 6000ppm water, more than most martian meteorites.
3) NWA 7034 matches basalts analyzed at Gusev Crater by the Mars Exploration Rover and the average martian crust measured by orbiters, unlike other martian meteorites. Its composition suggests
Similar to Compositional morphological analysis_central_peak_of _tycho_crater (20)
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Tr...Sérgio Sacani
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the
atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets
receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric
composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet
transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (Porb) of 12.76 days.
The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous Porb from TESS data. We
confirmed the transit signal and Porb using ground-based photometry with MuSCAT2 and MuSCAT3, and
validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as
well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope
and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host
star is inactive, with an X-ray-to-bolometric luminosity ratio of log 5.7 L L X bol » - . Joint analysis of the light
curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R⊕,a3σ mass upper limit of
3.9 M⊕, and an equilibrium temperature of 315 ± 6 K assuming zero albedo. The transmission spectroscopy metric
(TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small
list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Sérgio Sacani
We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a
bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from the Solar system with one of the
lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors
42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations
with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory,
as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of
12.76144 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 K. Gliese 12 b has excellent
future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar
compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool
stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy.
The importance of continents, oceans and plate tectonics for the evolution of...Sérgio Sacani
Within the uncertainties of involved astronomical and biological parameters, the Drake Equation
typically predicts that there should be many exoplanets in our galaxy hosting active, communicative
civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is
often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing
the importance of planetary tectonic style for biological evolution. We summarize growing evidence
that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern
plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated
emergence and evolution of complex species. We further suggest that both continents and oceans
are required for ACCs because early evolution of simple life must happen in water but late evolution
of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox
(1) by adding two additional terms to the Drake Equation: foc
(the fraction of habitable exoplanets
with significant continents and oceans) and fpt
(the fraction of habitable exoplanets with significant
continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by
demonstrating that the product of foc
and fpt
is very small (< 0.00003–0.002). We propose that the lack
of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on
exoplanets with primitive life.
A Giant Impact Origin for the First Subduction on EarthSérgio Sacani
Hadean zircons provide a potential record of Earth's earliest subduction 4.3 billion years ago. Itremains enigmatic how subduction could be initiated so soon after the presumably Moon‐forming giant impact(MGI). Earlier studies found an increase in Earth's core‐mantle boundary (CMB) temperature due to theaccumulation of the impactor's core, and our recent work shows Earth's lower mantle remains largely solid, withsome of the impactor's mantle potentially surviving as the large low‐shear velocity provinces (LLSVPs). Here,we show that a hot post‐impact CMB drives the initiation of strong mantle plumes that can induce subductioninitiation ∼200 Myr after the MGI. 2D and 3D thermomechanical computations show that a high CMBtemperature is the primary factor triggering early subduction, with enrichment of heat‐producing elements inLLSVPs as another potential factor. The models link the earliest subduction to the MGI with implications forunderstanding the diverse tectonic regimes of rocky planets.
Climate extremes likely to drive land mammal extinction during next supercont...Sérgio Sacani
Mammals have dominated Earth for approximately 55 Myr thanks to their
adaptations and resilience to warming and cooling during the Cenozoic. All
life will eventually perish in a runaway greenhouse once absorbed solar
radiation exceeds the emission of thermal radiation in several billions of
years. However, conditions rendering the Earth naturally inhospitable to
mammals may develop sooner because of long-term processes linked to
plate tectonics (short-term perturbations are not considered here). In
~250 Myr, all continents will converge to form Earth’s next supercontinent,
Pangea Ultima. A natural consequence of the creation and decay of Pangea
Ultima will be extremes in pCO2 due to changes in volcanic rifting and
outgassing. Here we show that increased pCO2, solar energy (F⨀;
approximately +2.5% W m−2 greater than today) and continentality (larger
range in temperatures away from the ocean) lead to increasing warming
hostile to mammalian life. We assess their impact on mammalian
physiological limits (dry bulb, wet bulb and Humidex heat stress indicators)
as well as a planetary habitability index. Given mammals’ continued survival,
predicted background pCO2 levels of 410–816 ppm combined with increased
F⨀ will probably lead to a climate tipping point and their mass extinction.
The results also highlight how global landmass configuration, pCO2 and F⨀
play a critical role in planetary habitability.
Constraints on Neutrino Natal Kicks from Black-Hole Binary VFTS 243Sérgio Sacani
The recently reported observation of VFTS 243 is the first example of a massive black-hole binary
system with negligible binary interaction following black-hole formation. The black-hole mass (≈10M⊙)
and near-circular orbit (e ≈ 0.02) of VFTS 243 suggest that the progenitor star experienced complete
collapse, with energy-momentum being lost predominantly through neutrinos. VFTS 243 enables us to
constrain the natal kick and neutrino-emission asymmetry during black-hole formation. At 68% confidence
level, the natal kick velocity (mass decrement) is ≲10 km=s (≲1.0M⊙), with a full probability distribution
that peaks when ≈0.3M⊙ were ejected, presumably in neutrinos, and the black hole experienced a natal
kick of 4 km=s. The neutrino-emission asymmetry is ≲4%, with best fit values of ∼0–0.2%. Such a small
neutrino natal kick accompanying black-hole formation is in agreement with theoretical predictions.
Detectability of Solar Panels as a TechnosignatureSérgio Sacani
In this work, we assess the potential detectability of solar panels made of silicon on an Earth-like
exoplanet as a potential technosignature. Silicon-based photovoltaic cells have high reflectance in the
UV-VIS and in the near-IR, within the wavelength range of a space-based flagship mission concept
like the Habitable Worlds Observatory (HWO). Assuming that only solar energy is used to provide
the 2022 human energy needs with a land cover of ∼ 2.4%, and projecting the future energy demand
assuming various growth-rate scenarios, we assess the detectability with an 8 m HWO-like telescope.
Assuming the most favorable viewing orientation, and focusing on the strong absorption edge in the
ultraviolet-to-visible (0.34 − 0.52 µm), we find that several 100s of hours of observation time is needed
to reach a SNR of 5 for an Earth-like planet around a Sun-like star at 10pc, even with a solar panel
coverage of ∼ 23% land coverage of a future Earth. We discuss the necessity of concepts like Kardeshev
Type I/II civilizations and Dyson spheres, which would aim to harness vast amounts of energy. Even
with much larger populations than today, the total energy use of human civilization would be orders of
magnitude below the threshold for causing direct thermal heating or reaching the scale of a Kardashev
Type I civilization. Any extraterrrestrial civilization that likewise achieves sustainable population
levels may also find a limit on its need to expand, which suggests that a galaxy-spanning civilization
as imagined in the Fermi paradox may not exist.
Jet reorientation in central galaxies of clusters and groups: insights from V...Sérgio Sacani
Recent observations of galaxy clusters and groups with misalignments between their central AGN jets
and X-ray cavities, or with multiple misaligned cavities, have raised concerns about the jet – bubble
connection in cooling cores, and the processes responsible for jet realignment. To investigate the
frequency and causes of such misalignments, we construct a sample of 16 cool core galaxy clusters and
groups. Using VLBA radio data we measure the parsec-scale position angle of the jets, and compare
it with the position angle of the X-ray cavities detected in Chandra data. Using the overall sample
and selected subsets, we consistently find that there is a 30% – 38% chance to find a misalignment
larger than ∆Ψ = 45◦ when observing a cluster/group with a detected jet and at least one cavity. We
determine that projection may account for an apparently large ∆Ψ only in a fraction of objects (∼35%),
and given that gas dynamical disturbances (as sloshing) are found in both aligned and misaligned
systems, we exclude environmental perturbation as the main driver of cavity – jet misalignment.
Moreover, we find that large misalignments (up to ∼ 90◦
) are favored over smaller ones (45◦ ≤ ∆Ψ ≤
70◦
), and that the change in jet direction can occur on timescales between one and a few tens of Myr.
We conclude that misalignments are more likely related to actual reorientation of the jet axis, and we
discuss several engine-based mechanisms that may cause these dramatic changes.
The solar dynamo begins near the surfaceSérgio Sacani
The magnetic dynamo cycle of the Sun features a distinct pattern: a propagating
region of sunspot emergence appears around 30° latitude and vanishes near the
equator every 11 years (ref. 1). Moreover, longitudinal flows called torsional oscillations
closely shadow sunspot migration, undoubtedly sharing a common cause2. Contrary
to theories suggesting deep origins of these phenomena, helioseismology pinpoints
low-latitude torsional oscillations to the outer 5–10% of the Sun, the near-surface
shear layer3,4. Within this zone, inwardly increasing differential rotation coupled with
a poloidal magnetic field strongly implicates the magneto-rotational instability5,6,
prominent in accretion-disk theory and observed in laboratory experiments7.
Together, these two facts prompt the general question: whether the solar dynamo is
possibly a near-surface instability. Here we report strong affirmative evidence in stark
contrast to traditional models8 focusing on the deeper tachocline. Simple analytic
estimates show that the near-surface magneto-rotational instability better explains
the spatiotemporal scales of the torsional oscillations and inferred subsurface
magnetic field amplitudes9. State-of-the-art numerical simulations corroborate these
estimates and reproduce hemispherical magnetic current helicity laws10. The dynamo
resulting from a well-understood near-surface phenomenon improves prospects
for accurate predictions of full magnetic cycles and space weather, affecting the
electromagnetic infrastructure of Earth.
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...Sérgio Sacani
In the Nice model of solar system formation, Uranus and Neptune undergo an orbital upheaval,
sweeping through a planetesimal disk. The region of the disk from which material is accreted by
the ice giants during this phase of their evolution has not previously been identified. We perform
direct N-body orbital simulations of the four giant planets to determine the amount and origin of solid
accretion during this orbital upheaval. We find that the ice giants undergo an extreme bombardment
event, with collision rates as much as ∼3 per hour assuming km-sized planetesimals, increasing the
total planet mass by up to ∼0.35%. In all cases, the initially outermost ice giant experiences the
largest total enhancement. We determine that for some plausible planetesimal properties, the resulting
atmospheric enrichment could potentially produce sufficient latent heat to alter the planetary cooling
timescale according to existing models. Our findings suggest that substantial accretion during this
phase of planetary evolution may have been sufficient to impact the atmospheric composition and
thermal evolution of the ice giants, motivating future work on the fate of deposited solid material.
Exomoons & Exorings with the Habitable Worlds Observatory I: On the Detection...Sérgio Sacani
The highest priority recommendation of the Astro2020 Decadal Survey for space-based astronomy
was the construction of an observatory capable of characterizing habitable worlds. In this paper series
we explore the detectability of and interference from exomoons and exorings serendipitously observed
with the proposed Habitable Worlds Observatory (HWO) as it seeks to characterize exoplanets, starting
in this manuscript with Earth-Moon analog mutual events. Unlike transits, which only occur in systems
viewed near edge-on, shadow (i.e., solar eclipse) and lunar eclipse mutual events occur in almost every
star-planet-moon system. The cadence of these events can vary widely from ∼yearly to multiple events
per day, as was the case in our younger Earth-Moon system. Leveraging previous space-based (EPOXI)
lightcurves of a Moon transit and performance predictions from the LUVOIR-B concept, we derive
the detectability of Moon analogs with HWO. We determine that Earth-Moon analogs are detectable
with observation of ∼2-20 mutual events for systems within 10 pc, and larger moons should remain
detectable out to 20 pc. We explore the extent to which exomoon mutual events can mimic planet
features and weather. We find that HWO wavelength coverage in the near-IR, specifically in the 1.4 µm
water band where large moons can outshine their host planet, will aid in differentiating exomoon signals
from exoplanet variability. Finally, we predict that exomoons formed through collision processes akin
to our Moon are more likely to be detected in younger systems, where shorter orbital periods and
favorable geometry enhance the probability and frequency of mutual events.
Emergent ribozyme behaviors in oxychlorine brines indicate a unique niche for...Sérgio Sacani
Mars is a particularly attractive candidate among known astronomical objects
to potentially host life. Results from space exploration missions have provided
insights into Martian geochemistry that indicate oxychlorine species, particularly perchlorate, are ubiquitous features of the Martian geochemical landscape. Perchlorate presents potential obstacles for known forms of life due to
its toxicity. However, it can also provide potential benefits, such as producing
brines by deliquescence, like those thought to exist on present-day Mars. Here
we show perchlorate brines support folding and catalysis of functional RNAs,
while inactivating representative protein enzymes. Additionally, we show
perchlorate and other oxychlorine species enable ribozyme functions,
including homeostasis-like regulatory behavior and ribozyme-catalyzed
chlorination of organic molecules. We suggest nucleic acids are uniquely wellsuited to hypersaline Martian environments. Furthermore, Martian near- or
subsurface oxychlorine brines, and brines found in potential lifeforms, could
provide a unique niche for biomolecular evolution.
Continuum emission from within the plunging region of black hole discsSérgio Sacani
The thermal continuum emission observed from accreting black holes across X-ray bands has the potential to be leveraged as a
powerful probe of the mass and spin of the central black hole. The vast majority of existing ‘continuum fitting’ models neglect
emission sourced at and within the innermost stable circular orbit (ISCO) of the black hole. Numerical simulations, however,
find non-zero emission sourced from these regions. In this work, we extend existing techniques by including the emission
sourced from within the plunging region, utilizing new analytical models that reproduce the properties of numerical accretion
simulations. We show that in general the neglected intra-ISCO emission produces a hot-and-small quasi-blackbody component,
but can also produce a weak power-law tail for more extreme parameter regions. A similar hot-and-small blackbody component
has been added in by hand in an ad hoc manner to previous analyses of X-ray binary spectra. We show that the X-ray spectrum
of MAXI J1820+070 in a soft-state outburst is extremely well described by a full Kerr black hole disc, while conventional
models that neglect intra-ISCO emission are unable to reproduce the data. We believe this represents the first robust detection of
intra-ISCO emission in the literature, and allows additional constraints to be placed on the MAXI J1820 + 070 black hole spin
which must be low a• < 0.5 to allow a detectable intra-ISCO region. Emission from within the ISCO is the dominant emission
component in the MAXI J1820 + 070 spectrum between 6 and 10 keV, highlighting the necessity of including this region. Our
continuum fitting model is made publicly available.
UiPath Test Automation using UiPath Test Suite series, part 5DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 5. In this session, we will cover CI/CD with devops.
Topics covered:
CI/CD with in UiPath
End-to-end overview of CI/CD pipeline with Azure devops
Speaker:
Lyndsey Byblow, Test Suite Sales Engineer @ UiPath, Inc.
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
How to Get CNIC Information System with Paksim Ga.pptxdanishmna97
Pakdata Cf is a groundbreaking system designed to streamline and facilitate access to CNIC information. This innovative platform leverages advanced technology to provide users with efficient and secure access to their CNIC details.
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Speck&Tech
ABSTRACT: A prima vista, un mattoncino Lego e la backdoor XZ potrebbero avere in comune il fatto di essere entrambi blocchi di costruzione, o dipendenze di progetti creativi e software. La realtà è che un mattoncino Lego e il caso della backdoor XZ hanno molto di più di tutto ciò in comune.
Partecipate alla presentazione per immergervi in una storia di interoperabilità, standard e formati aperti, per poi discutere del ruolo importante che i contributori hanno in una comunità open source sostenibile.
BIO: Sostenitrice del software libero e dei formati standard e aperti. È stata un membro attivo dei progetti Fedora e openSUSE e ha co-fondato l'Associazione LibreItalia dove è stata coinvolta in diversi eventi, migrazioni e formazione relativi a LibreOffice. In precedenza ha lavorato a migrazioni e corsi di formazione su LibreOffice per diverse amministrazioni pubbliche e privati. Da gennaio 2020 lavora in SUSE come Software Release Engineer per Uyuni e SUSE Manager e quando non segue la sua passione per i computer e per Geeko coltiva la sua curiosità per l'astronomia (da cui deriva il suo nickname deneb_alpha).
Communications Mining Series - Zero to Hero - Session 1DianaGray10
This session provides introduction to UiPath Communication Mining, importance and platform overview. You will acquire a good understand of the phases in Communication Mining as we go over the platform with you. Topics covered:
• Communication Mining Overview
• Why is it important?
• How can it help today’s business and the benefits
• Phases in Communication Mining
• Demo on Platform overview
• Q/A
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
Let's Integrate MuleSoft RPA, COMPOSER, APM with AWS IDP along with Slackshyamraj55
Discover the seamless integration of RPA (Robotic Process Automation), COMPOSER, and APM with AWS IDP enhanced with Slack notifications. Explore how these technologies converge to streamline workflows, optimize performance, and ensure secure access, all while leveraging the power of AWS IDP and real-time communication via Slack notifications.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
Building RAG with self-deployed Milvus vector database and Snowpark Container...Zilliz
This talk will give hands-on advice on building RAG applications with an open-source Milvus database deployed as a docker container. We will also introduce the integration of Milvus with Snowpark Container Services.
Unlock the Future of Search with MongoDB Atlas_ Vector Search Unleashed.pdfMalak Abu Hammad
Discover how MongoDB Atlas and vector search technology can revolutionize your application's search capabilities. This comprehensive presentation covers:
* What is Vector Search?
* Importance and benefits of vector search
* Practical use cases across various industries
* Step-by-step implementation guide
* Live demos with code snippets
* Enhancing LLM capabilities with vector search
* Best practices and optimization strategies
Perfect for developers, AI enthusiasts, and tech leaders. Learn how to leverage MongoDB Atlas to deliver highly relevant, context-aware search results, transforming your data retrieval process. Stay ahead in tech innovation and maximize the potential of your applications.
#MongoDB #VectorSearch #AI #SemanticSearch #TechInnovation #DataScience #LLM #MachineLearning #SearchTechnology
“An Outlook of the Ongoing and Future Relationship between Blockchain Technologies and Process-aware Information Systems.” Invited talk at the joint workshop on Blockchain for Information Systems (BC4IS) and Blockchain for Trusted Data Sharing (B4TDS), co-located with with the 36th International Conference on Advanced Information Systems Engineering (CAiSE), 3 June 2024, Limassol, Cyprus.
1. RESEARCH COMMUNICATIONS
Compositional and morphological spicuous central peak, sharply sculptured crater walls and
rims with widespread ejecta blanket around its exterior1.
analysis of high resolution remote Its central peak is believed to contain deep-seated mate-
sensing data over central peak of rial excavated during the impact and has been reported to
Tycho crater on the Moon: have compositional assemblage of gabbroic nature with
anorthositic rocks on its base2–7. The peak is also charac-
implications for understanding terized by average titanium content > 1 wt%, showing the
lunar interior presence of mantle-derived mafic material of plutonic/
volcanic origin8. Earlier studies on the Tycho crater indi-
Prakash Chauhan1,*, Prabhjot Kaur1, cated the possibility of volcanic activity on the central
peak using photogeological studies of high resolution
Neeraj Srivastava2, Satadru Bhattacharya1,
lunar orbiter photographs. Multiphase development of the
Ajai1, A. S. Kiran Kumar1 and J. N. Goswami2 central peak, involving late stage volcanism was inferred
1
Space Applications Centre (ISRO), Jodhpur Tekra, from Lunar Orbiter V images, which also revealed a pos-
Ahmedabad 380 015, India
2
Physical Research Laboratory, Navarangpura, Ahmedabad 380 009, India
sible lava pond on the central peak9. In a subsequent
study, Tycho crater floor, rim and ejecta blanket using
Tycho is a young impact crater of Copernican age Lunar Orbiter V photographs were mapped and dated.
(~ 110 Ma) in the southern highlands of the Moon. The Many lava flows and lava lakes on the crater floor, rim,
crater has a well-developed central peak with an alti- terraced walls and a lava pond within the central peak
tude of ~ 2 km. Central peaks of large lunar craters were identified. Based on this it was concluded that the
are ideal to study the deep-seated crustal material. In volcanism associated with Tycho crater may have been
this study we report the results of an integrated triggered by a large impact, which tapped a shallow sub-
morphological and compositional analysis for the cen- surface source of magma10. Recent studies using very
tral peak of the Tycho crater by using high-resolution high resolution Lunar Reconnaissance Orbiter Narrow
data from Terrain Mapping Camera (TMC) and Angle Camera (LRO NAC) data suggest that the impact
Moon Mineralogy Mapper (M3) on-board Chandra-
melt features around the Tycho are much younger than
yaan-1 along with data from Narrow Angle Camera
(NAC) of Lunar Reconnaissance Orbiter. Our analysis the ejecta blanket outside the crater11. The evidences for
shows various morphological features associated with volcanic activity were also studied using morphology and
volcanism in the form of volcanic vents, domes, clasts, morphometric analysis for 580 lunar craters (with diame-
impact melt lava ponds showing distinct cooling ter between 40 and 100 km) and only three craters,
cracks, and flow patterns on and around this central namely Lansberg (0.3°S, 26.6°W), Plinius (15.4°N,
peak. Compositionally, M3 data suggest that the cen- 23.7°E) situated in the mare region and Icarus (5.3°S,
tral peak is highly heterogeneous and dominated by 173.2°W) situated in highland region, were considered
high-Ca pyroxene-rich rocks. The base of the central to be plausibly modified or formed due to volcanic
peak is anorthositic in nature. These new morphologi- activity12.
cal and mineralogical evidences suggest that the cen- In this communication, we report results of a combined
tral peak of the Tycho crater has diverse morphology
morphological and compositional analysis of new high
and mineralogical variability, suggesting multiphase
modifications subsequent to the crater formation. The resolution data over the central peak of the Tycho crater,
presence of diverse mafic lithologies on the central to provide evidence for features associated with impact-
peak situated, in a predominantly anorthositic geo- induced volcanism/modifications using Terrain Mapping
logical setting, suggests exposure of the subsurface Camera (TMC) and Moon Mineralogy Mapper (M3) data
pluton during the impact and thus provides insight from Chandrayaan-1 and NAC images of the LRO mis-
into the composition of the lunar inner crust. sion. Our study provides direct evidence of volcanism on
this central peak, in the form of volcanic vents, clast/
Keywords: Central peak, Chandrayaan-1, lunar inte- boulders, lava ponds showing prominent cooling cracks
rior, remote sensing, Tycho crater. and lava channels with well-defined flow fronts at several
locations. The compositional study using M3 data further
TYCHO, a prominent impact crater of ~ 100 km diameter shows the presence of heterogeneous mafic lithologies on
is located in the southern highlands (43.4°S, 11.4°W) on the central peak, suggesting exposure of lunar inner
the near side of the Moon and is considered as the classic crustal material.
example of a large impact carter. It is a young Coperni- Chandrayaan-1 TMC data with 5 m spatial resolution
can crater (~ 110 Ma) with well-developed bright ray using three different stereoscopic views separated by
patterns and intact crater morphology exhibiting a con- ± 26° have been used to study the detailed morphological
features. The TMC sensor operates in the panchromatic
mode with a wide spectral range of 0.5–0.85 μm and cov-
*For correspondence. (e-mail: prakash@sac.isro.gov.in) ered a 20 km wide swath on the lunar surface. The three
CURRENT SCIENCE, VOL. 102, NO. 7, 10 APRIL 2012 1041
2. RESEARCH COMMUNICATIONS
Figure 1. a, Chandrayaan-1 TMC data mosaic of Tycho crater. b, Three-dimensional image of Tycho
central peak with vertical exaggeration factor of 5.0 showing two distinct lava ponds. Flow direction and
pattern is marked with a thick dotted line. A set of fractures is marked with thin dotted lines.
stereo triplets of orbit number 2877 of TMC data were where ρ (λ) is the wavelength (λ)-dependent apparent
further used to generate digital elevation model (DEM) reflectance, L(λ) is the spectral radiance, E0(λ) is the
of the lunar surface at 25 m posting interval13. Addition- incoming solar flux on the surface of the Moon and θ s is
ally, LRO NAC datasets numbered M114031031LC, the solar zenith angle. Spectral signatures of the central
M111661378LE, M127008391LE and M104584909LE, peak of the Tycho crater have been generated using re-
obtained from the LRO website (http://wms.lroc.asu.edu), flectance data. Spectra have been limited up to 2.5 μm
covering the central peak of Tycho crater and crater floor wavelength range to avoid thermal emission effects. Most
have been used for morphological analysis. Whereas of the sampled spectra were 3 × 3 pixel averages, whereas
TMC–DEM has provided a perspective view of the cen- some were from 1 × 1 pixel due to smaller target size.
tral peak (Figure 1), essential for the study of geologic These collected spectra were further used to assess the
settings and identification of various morphological fea- nature, distribution and association of the various minera-
tures. LRO NAC data have enabled us to have a closer logical entities found on and around the Tycho crater.
look at them from different phase angles, at a very high The major lunar minerals consist of pyroxene, olivine,
spatial resolution of ~ 0.5 m (Figures 2 and 3). Morpho- plagioclase and spinel with several other minor minerals
logical parameters such as slope of the central rise have like magnetite, ilmenite, etc. Spectroscopic remote sens-
been generated and used for locating accumulation zones ing is one of the best tools to study planetary surface
to understand the process of formation of lava ponds on composition. The spectral properties of these minerals
the central rise (Figure 4). depend on their crystal structure and type of ions present
For compositional analysis we have used hyperspectral in the crystallographic site of the minerals17. Olivine
data from the M3 sensor, guest instrument from NASA, exhibits three overlapping absorption bands around
on-board Chandrayaan-114,15. M3 having the spectral 1.0 μm and lacks absorption band around 2.0 μm, Low-
range of 0.43–3.0 μm with 85 spectral bands acquired the Ca pyroxenes exhibit two absorption bands between 0.90
spectral radiance data of the Moon surface in global and 0.93 μm, and 1.80 and 2.10 μm, and high-Ca clino-
mode, with 140 m/pixel spatial resolution from a 100 km pyroxene displays absorption bands between 0.91 and
orbit. For this study, the M3 Level-1b radiance data were 1.06 μm and 1.97 and 2.35 μm (refs 17 and 18).
converted into the apparent reflectance by normalizing A variety of analytic tools have been developed to
the radiance values to incoming solar flux corresponding solve the mineralogical puzzles of the remote bodies
to spectral bands of the M3 data16. The apparent reflec- using the positions of absorption bands present in reflec-
tance was converted using tance spectra and their relative band areas19–21, or by the
deconvolution of near-infrared spectra into their compo-
ρ (λ) = πL(λ)/E0(λ)cos(θ s), (1) nent absorption bands22. For deriving mineralogical
1042 CURRENT SCIENCE, VOL. 102, NO. 7, 10 APRIL 2012
3. RESEARCH COMMUNICATIONS
Figure 2. a, High-resolution view of lava pond 1 using Chandrayaan-1 TMC data. b, Very high-resolution view of the
lava pond 1 from LROC NAC image. Possible vent for the lava flow is marked with a solid circle. Lava flow directions
are marked with a thick dotted line; and clasts deposited at the base of the flank are marked with a dotted circle. c, Close
view of the lava pond showing fractures or fissures.
Figure 3. a, High-resolution TMC image for lava pond 2 identified on the summit of the central peak clearly showing
contractional cracks and volcanic domes. b, LROC NAC image showing similar features in more detail along with lava
channels on the slopes of the central peak. c, LROC NAC image of same area showing domes with different sun angles.
information and characterization of the reflectance spec- and band II respectively. Continuum removal has been
tra, band analysis technique using scatter plot of central performed to isolate specific absorption features and is
wavelengths for the first and second absorption features, accomplished by dividing out a straight line continuum
developed by earlier workers is quite useful21. We per- tangent on either side of the absorption band. Band cen-
formed a continuum removal technique on the reflectance tres were calculated by fitting a third order polynomial to
spectra, to derive the central wavelengths around the first ~ 10–20 points on either side of a visually determined
and second pyroxene absorption features called band I absorption centre or reflectance minimum.
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4. RESEARCH COMMUNICATIONS
Figure 4. a, Digital Elevation Model (DEM) of the central peak. b, Slope map generated from TMC DEM.
Locations (1) and (2) marked on slope map are depressions with gentle slope leading to accumulation for lava.
Figure 1 a shows a mosaic of TMC data strips covering flank, suggesting that slope instability resulted into the
the Tycho crater and Figure 1 b shows the three- continuous debris flow from the flanks. The possible
dimensional view of the central peak, generated by drap- source of the lava channel is not clear; however, the pres-
ing the TMC panchromatic image over DEM. Using the ence of features like domes, fractures and a small circular
DEM data a slope map for the central peak has been gen- depression (marked as thin dotted line in Figure 3 b) in
erated and is shown in Figure 4 b. Two accumulation the area points towards the possible sources of the lava
zones having lesser slope have been identified using the channel. The other possible mode of formation of this
slope map and are marked in Figure 4 b. Two lava ponds channel is the flow of material from lava pond 2 first fill-
(marked 1 and 2 in Figure 1 b), with an aerial extent of ing the circular depression followed by flow of the exces-
~ 1.4 and 0.5 sq. km respectively, have been identified sive material following the slope of the terrain. Figure
and are associated with accumulation zones in the slope 3 a–c of lava pond 2 at the summit of the central peak
image. Lava pond 1 is located on the northwestern edge also shows peripheral contractional cracks associated
of the central peak, whereas lava pond 2 is located at the with domes and clasts/boulders in close proximity. Figure
summit of the peak. Figure 2 a and b of lava pond 1, from 3 b shows a flow channel almost identical to the lava
TMC and LRO NAC data, clearly shows signatures of drainage channel having wrinkled/ropey appearance, sug-
flow patterns associated with lava flow, clast/boulders gesting the viscous nature of the lava compared to the
and a slightly raised, inclined, volcanic vent of ~ 50 m lava flows in mare basins. The floor of the crater also ex-
diameter (Figure 2 a), surrounded by a high density of hibits hummocky flow pattern and well-developed frac-
boulders. Some of the central peak areas are found to be tures or contractional cracks (marked in Figure 1 b)
covered with clast or boulders of varying size. The flow developed as a result of cooling. These evidences suggest
structures have been mapped and are marked in Figures the volcanic nature of the morphological entities. The
2 b and 3 b, with their possible flow direction indicated ropey appearance and contractional cracks as observed on
by arrows. The mapped flow structures follow the slope the central peak and floor of the Tycho crater match well
gradient of the flanks of the central peak. Possible vent with the flow patterns associated with terrestrial lava.
for the lava flow which might have resulted into the for- Compositional variability of the Tycho crater is shown
mation of the lava pond 1 is also marked in Figure 2 b. in a RGB combination generated using bands of the
Figure 2 c, the high resolution NAC image, shows the major absorption wavelengths (R = 1000, G = 1250 and
stratigraphic relationship between lava flow and overlaid B = 2000 nm) and draped over DEM, as shown in Figure
clast, suggesting a time difference between the lava flow 5 a. Figure 5 b and c shows a closer view of the central
and deposition of the clasts embedded in the lava. It is peak and the spectra collected from the various minera-
evident from Figure 2 b that the lava flow must be older logical entities respectively. In Figure 5 a, pyroxene-
than the clasts/boulders which are embedded in the lava dominated lithologies are highlighted in green to yellow
pond due to debris flow from the flank. The textural colours, and pink to blue shades represent anorthositic
information suggests that at the time of deposition of the terrain. It is observed from Figure 5 a that the dominant
clasts, the lava must have been in a semi-solid state and lithology present on the central peak is pyroxene; how-
not completely solidified leading to partial cementing of ever, the floor of the crater shows mixed lithology of
the clasts/boulders. Also some boulders can be easily anorthosite and pyroxene. The mineralogical diversity
seen (marked in Figure 2 b) deposited at the base of the on the central peak has been captured in the
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5. RESEARCH COMMUNICATIONS
Figure 5. a, Chandrayaan-1 M3 FCC generated using (1000, 1250 and 2000 nm bands) as RGB combination and draped
over the radius image from M3 for a 3D perspective view of the Tycho crater. Greenish-yellow colour shows spatial dis-
tribution of mafic minerals. b, Detailed view of central peak in FCC image and locations for spectra collected. c, Spectral
reflectance curves of the lava ponds 1 and 2 along with spectra of Tycho crater floor and plagioclase-rich blocks.
pyroxene (Figure 5 c). Spectrum 4 represents the plagio-
clase-rich flank, as it shows a prominent absorption fea-
ture around 1.3 μm. Similar results were also reported in
a previous work using SELENE Multiband Imager (MI)
data7. Apart from the 1.3 μm plagioclase feature, spec-
trum 4 also shows 1 and 2 μm absorption due to mixing
with pyroxene. However, this information could not be
captured by SELENE MI data due to lack of bands be-
yond 1.5 μm.
Band centres calculated as described earlier were used
to determine the type of pyroxene present in the study
area. Since for both types of pyroxene, the absorption
features are different, the scatter plot of absorption at
Figure 6. Two dimensional scatter plot of band centres of Pyroxene bands II and I is useful in determining the type of pyrox-
absorption features around 1000 nm (Band I) and 2000 nm (Band II).
Band centre data from the flank area plots mostly within the pure ene20,23. Band II position is directly related to pyroxene
pyroxene range whereas central peak band centres deviates from the composition, while band I is sensitive to the presence of
regular trend. relative composition and abundance of olivine and pyrox-
ene component. A large number of spectra was collected
spectra, collected at various locations, as shown in Figure from various part of the Tycho crater and a 2D scatter
5 b. Spectra collected from the central peak region show plot of band I and band II centres was generated, as
prominent absorption at 1 and 2 μm corresponding to shown in Figure 6. The band centre positions of spectra
CURRENT SCIENCE, VOL. 102, NO. 7, 10 APRIL 2012 1045
6. RESEARCH COMMUNICATIONS
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