The age of Jupiter, the largest planet in our Solar System, is still
unknown. Gas-giant planet formation likely involved the growth
of large solid cores, followed by the accumulation of gas onto
these cores. Thus, the gas-giant cores must have formed before
dissipation of the solar nebula, which likely occurred within less
than 10 My after Solar System formation. Although such rapid
accretion of the gas-giant cores has successfully been modeled,
until now it has not been possible to date their formation. Here,
using molybdenum and tungsten isotope measurements on iron
meteorites, we demonstrate that meteorites derive from two
genetically distinct nebular reservoirs that coexisted and remained
spatially separated between ∼1My and ∼3–4My after Solar System
formation. The most plausible mechanism for this efficient separation
is the formation of Jupiter, opening a gap in the disk and
preventing the exchange of material between the two reservoirs.
As such, our results indicate that Jupiter’s core grew to ∼20 Earth
masses within <1 My, followed by amore protracted growth to ∼50
Earth masses until at least ∼3–4 My after Solar System formation.
Thus, Jupiter is the oldest planet of the Solar System, and its solid
core formed well before the solar nebula gas dissipated, consistent
with the core accretion model for giant planet formation.
Isotopic evolution of the protoplanetary disk and the building blocks of Eart...Sérgio Sacani
Nucleosynthetic isotope variability among Solar System objects
is often used to probe the genetic relationship between meteorite
groups and the rocky planets (Mercury, Venus, Earth and Mars),
which, in turn, may provide insights into the building blocks
of the Earth–Moon system1–5. Using this approach, it has been
inferred that no primitive meteorite matches the terrestrial
composition and the protoplanetary disk material from which
Earth and the Moon accreted is therefore largely unconstrained6
.
This conclusion, however, is based on the assumption that the
observed nucleosynthetic variability of inner-Solar-System objects
predominantly reflects spatial heterogeneity. Here we use the
isotopic composition of the refractory element calcium to show that
the nucleosynthetic variability in the inner Solar System primarily
reflects a rapid change in the mass-independent calcium isotope
composition of protoplanetary disk solids associated with early
mass accretion to the proto-Sun. We measure the mass-independent
48Ca/44Ca ratios of samples originating from the parent bodies of
ureilite and angrite meteorites, as well as from Vesta, Mars and
Earth, and find that they are positively correlated with the masses
of their parent asteroids and planets, which are a proxy of their
accretion timescales. This correlation implies a secular evolution of
the bulk calcium isotope composition of the protoplanetary disk in
the terrestrial planet-forming region. Individual chondrules from
ordinary chondrites formed within one million years of the collapse
of the proto-Sun7
reveal the full range of inner-Solar-System massindependent
48Ca/44Ca ratios, indicating a rapid change in the
composition of the material of the protoplanetary disk. We infer
that this secular evolution reflects admixing of pristine outer-SolarSystem
material into the thermally processed inner protoplanetary
disk associated with the accretion of mass to the proto-Sun. The
identical calcium isotope composition of Earth and the Moon
reported here is a prediction of our model if the Moon-forming
impact involved protoplanets or precursors that completed their
accretion near the end of the protoplanetary disk’s lifetime.
On the theory_and_future_cosmic_planet_formationSérgio Sacani
A Terra chegou cedo para a festa no universo em evolução. De acordo com um novo estudo teórico, quando o nosso Sistema Solar nasceu a 4.6 bilhões de anos atrás, somente 8% dos planetas possivelmente habitáveis que serão formados no universo, existiam. E, a festa não terminaria até quando o Sol queimasse por outros 6 bilhões de anos. A totalidade desses planetas, 92%, não tinham nascido.
Essa conclusão é baseada no acesso dos dados coletados pelo Telescópio Espacial Hubble da NASA e o prolífico caçador de exoplanetas, o Observatório Espacial Kepler.
“Nossa principal motivação foi entender o lugar da Terra no contexto do resto do universo”, disse o autor do estudo Peter Behroozi do Space Telescope Science Institute (STScI), em Baltimore, Maryland, “Comparado a todos os planetas que irão se formar no universo, a Terra, na verdade chegou cedo”.
Olhando distante no espaço e no tempo, o Hubble, tem dado aos astrônomos um verdadeiro “álbum de família”, das observações da galáxia que mostra a história da formação do universo à medida que as galáxias cresciam. Os dados mostram que o universo estava gerando estrelas numa taxa elevada a 10 bilhões de anos atrás, mas a fração do gás hidrogênio e hélio do universo que estava envolvida era muito baixa. Hoje, o nascimento de estrelas está acontecendo numa taxa muito mais lenta do que a muito tempo atrás, mas existe muito gás deixado para trás disponível que o universo continuará gerando estrelas e planetas por muito tempo ainda.
This document summarizes evidence that submillimeter galaxies (SMGs) at redshift 3-6 may be progenitors of compact quiescent galaxies observed at redshift 2. It compares properties of a sample of z~2 quiescent galaxies with a statistical sample of z>3 SMGs in the COSMOS field. It finds that the formation redshifts of the z~2 galaxies match the observed redshift distribution of z>3 SMGs. It also finds that the space densities and properties such as sizes, stellar masses, and internal velocities of the two populations are consistent with an evolutionary connection, assuming SMG starbursts have a duty cycle of 42+40 Myr. This suggests SMGs may represent an early burst
This document provides an overview of mineralogy and the definition of a mineral. It begins by explaining that mineralogy is the study of natural, solid, crystalline materials. It then defines a mineral as a naturally occurring, homogeneous solid with a definite but generally not fixed chemical composition and ordered atomic arrangement, usually formed by inorganic processes. The document discusses several key aspects of minerals, including their origin from the Big Bang, properties that can be examined in hand specimens like crystal form and hardness, and concepts like stoichiometry and polymorphism.
Artigo descreve a descoberta de um sistema de anéis 200 vezes maior do que o sistema de anéis de Saturno num exoplaneta orbitando a jovem estrela J1407
This paper presents summation of twenty-one years investigation of the unique gold and diamondbearing
Agit Khangay and Khuree Mandal astropipes of Mongolia. These astropipe geostructures are as
selective examples amongst for four impact meteorite craters of Mongolia (Figure 1): Agit Khangay (10 km in
diameter, 470
38' N; 960
05' E), Khuree Mandal (D=11 km; 460
28' N; 980
25' E), Bayan Khuree (D=1 km; 440
06' N; 1090
36' E), and Tsenkher (D=7 km; 980
21' N; 430
36' E). The term “astropipes” [1] is a neologism and
new scientific discovery in Earth science and these geostructures are outlandish in certain aspects. Particularly
the Agit Khangay and Khuree Mandal astropipes are genuine “meteorite crater” geostructures but they also
contain kimberlite diamonds and gold. Suevite-like (agizite) rocks from the astropipes contain such minerals, as
coesite, stishovite, moissanite (0.6 mm), kamacite, tektite, khamravaevite (mineral of meteorite-titanic carbon),
graphite-2H, chondrite, picroilmenite, pyrope, phlogopite, khangaites (tektites, 1.0-3.0 mm in size), olivine, etc
[2]-[3]. Most panned samples and hand specimens contain fine diamonds with octahedral habit (0.2-0.5 mm,
6.4 mg or 0.034-0.1 carat) and gold (from 0.13 to 6.33-32.0 g/t). Of special interest is the larger number of the
black magnetic balls (0.05-5.0 mm) are characterized by high content of Ti, Fe, Co, Ni, Cu, Mn, Mg, Cd, Ga,
Cl, Al, Si, K. These described meteorite craters possess reliable topographic, geological, mineralogical,
geochemical, and aerospace mapping data, also some geophysical and petrological features (especially shock
metamorphism) have been found, all of which indicate that these geostructures are a proven new type of gold
and diamond-bearing impact geostructure, termed here “astropipes”. The essence of the phenomenon is
mantle-crust mix and fluidization of the combined nucleosynthesis-magmatic evolution-palingenesis interaction.
The identification of_93_day_periodic_photometric_variability_for_yso_ylw_16aSérgio Sacani
This study identifies a 93 day periodic photometric variability in the Class I young stellar object (YSO) YLW 16A in the Rho Ophiuchus star forming region. Light curve analysis reveals variations of ~0.5 magnitudes in the Ks band over this period. The authors propose a triple system model consisting of an inner binary with a 93 day period eclipsed by a warped circumbinary disk, with a tertiary companion at ~40 AU responsible for warping the disk. This model is similar to one previously proposed for another YSO, WL 4, and may indicate such triple systems with eclipsing disks are common around young stars. Understanding these systems can provide insights into stellar and planetary formation and evolution.
Isotopic evolution of the protoplanetary disk and the building blocks of Eart...Sérgio Sacani
Nucleosynthetic isotope variability among Solar System objects
is often used to probe the genetic relationship between meteorite
groups and the rocky planets (Mercury, Venus, Earth and Mars),
which, in turn, may provide insights into the building blocks
of the Earth–Moon system1–5. Using this approach, it has been
inferred that no primitive meteorite matches the terrestrial
composition and the protoplanetary disk material from which
Earth and the Moon accreted is therefore largely unconstrained6
.
This conclusion, however, is based on the assumption that the
observed nucleosynthetic variability of inner-Solar-System objects
predominantly reflects spatial heterogeneity. Here we use the
isotopic composition of the refractory element calcium to show that
the nucleosynthetic variability in the inner Solar System primarily
reflects a rapid change in the mass-independent calcium isotope
composition of protoplanetary disk solids associated with early
mass accretion to the proto-Sun. We measure the mass-independent
48Ca/44Ca ratios of samples originating from the parent bodies of
ureilite and angrite meteorites, as well as from Vesta, Mars and
Earth, and find that they are positively correlated with the masses
of their parent asteroids and planets, which are a proxy of their
accretion timescales. This correlation implies a secular evolution of
the bulk calcium isotope composition of the protoplanetary disk in
the terrestrial planet-forming region. Individual chondrules from
ordinary chondrites formed within one million years of the collapse
of the proto-Sun7
reveal the full range of inner-Solar-System massindependent
48Ca/44Ca ratios, indicating a rapid change in the
composition of the material of the protoplanetary disk. We infer
that this secular evolution reflects admixing of pristine outer-SolarSystem
material into the thermally processed inner protoplanetary
disk associated with the accretion of mass to the proto-Sun. The
identical calcium isotope composition of Earth and the Moon
reported here is a prediction of our model if the Moon-forming
impact involved protoplanets or precursors that completed their
accretion near the end of the protoplanetary disk’s lifetime.
On the theory_and_future_cosmic_planet_formationSérgio Sacani
A Terra chegou cedo para a festa no universo em evolução. De acordo com um novo estudo teórico, quando o nosso Sistema Solar nasceu a 4.6 bilhões de anos atrás, somente 8% dos planetas possivelmente habitáveis que serão formados no universo, existiam. E, a festa não terminaria até quando o Sol queimasse por outros 6 bilhões de anos. A totalidade desses planetas, 92%, não tinham nascido.
Essa conclusão é baseada no acesso dos dados coletados pelo Telescópio Espacial Hubble da NASA e o prolífico caçador de exoplanetas, o Observatório Espacial Kepler.
“Nossa principal motivação foi entender o lugar da Terra no contexto do resto do universo”, disse o autor do estudo Peter Behroozi do Space Telescope Science Institute (STScI), em Baltimore, Maryland, “Comparado a todos os planetas que irão se formar no universo, a Terra, na verdade chegou cedo”.
Olhando distante no espaço e no tempo, o Hubble, tem dado aos astrônomos um verdadeiro “álbum de família”, das observações da galáxia que mostra a história da formação do universo à medida que as galáxias cresciam. Os dados mostram que o universo estava gerando estrelas numa taxa elevada a 10 bilhões de anos atrás, mas a fração do gás hidrogênio e hélio do universo que estava envolvida era muito baixa. Hoje, o nascimento de estrelas está acontecendo numa taxa muito mais lenta do que a muito tempo atrás, mas existe muito gás deixado para trás disponível que o universo continuará gerando estrelas e planetas por muito tempo ainda.
This document summarizes evidence that submillimeter galaxies (SMGs) at redshift 3-6 may be progenitors of compact quiescent galaxies observed at redshift 2. It compares properties of a sample of z~2 quiescent galaxies with a statistical sample of z>3 SMGs in the COSMOS field. It finds that the formation redshifts of the z~2 galaxies match the observed redshift distribution of z>3 SMGs. It also finds that the space densities and properties such as sizes, stellar masses, and internal velocities of the two populations are consistent with an evolutionary connection, assuming SMG starbursts have a duty cycle of 42+40 Myr. This suggests SMGs may represent an early burst
This document provides an overview of mineralogy and the definition of a mineral. It begins by explaining that mineralogy is the study of natural, solid, crystalline materials. It then defines a mineral as a naturally occurring, homogeneous solid with a definite but generally not fixed chemical composition and ordered atomic arrangement, usually formed by inorganic processes. The document discusses several key aspects of minerals, including their origin from the Big Bang, properties that can be examined in hand specimens like crystal form and hardness, and concepts like stoichiometry and polymorphism.
Artigo descreve a descoberta de um sistema de anéis 200 vezes maior do que o sistema de anéis de Saturno num exoplaneta orbitando a jovem estrela J1407
This paper presents summation of twenty-one years investigation of the unique gold and diamondbearing
Agit Khangay and Khuree Mandal astropipes of Mongolia. These astropipe geostructures are as
selective examples amongst for four impact meteorite craters of Mongolia (Figure 1): Agit Khangay (10 km in
diameter, 470
38' N; 960
05' E), Khuree Mandal (D=11 km; 460
28' N; 980
25' E), Bayan Khuree (D=1 km; 440
06' N; 1090
36' E), and Tsenkher (D=7 km; 980
21' N; 430
36' E). The term “astropipes” [1] is a neologism and
new scientific discovery in Earth science and these geostructures are outlandish in certain aspects. Particularly
the Agit Khangay and Khuree Mandal astropipes are genuine “meteorite crater” geostructures but they also
contain kimberlite diamonds and gold. Suevite-like (agizite) rocks from the astropipes contain such minerals, as
coesite, stishovite, moissanite (0.6 mm), kamacite, tektite, khamravaevite (mineral of meteorite-titanic carbon),
graphite-2H, chondrite, picroilmenite, pyrope, phlogopite, khangaites (tektites, 1.0-3.0 mm in size), olivine, etc
[2]-[3]. Most panned samples and hand specimens contain fine diamonds with octahedral habit (0.2-0.5 mm,
6.4 mg or 0.034-0.1 carat) and gold (from 0.13 to 6.33-32.0 g/t). Of special interest is the larger number of the
black magnetic balls (0.05-5.0 mm) are characterized by high content of Ti, Fe, Co, Ni, Cu, Mn, Mg, Cd, Ga,
Cl, Al, Si, K. These described meteorite craters possess reliable topographic, geological, mineralogical,
geochemical, and aerospace mapping data, also some geophysical and petrological features (especially shock
metamorphism) have been found, all of which indicate that these geostructures are a proven new type of gold
and diamond-bearing impact geostructure, termed here “astropipes”. The essence of the phenomenon is
mantle-crust mix and fluidization of the combined nucleosynthesis-magmatic evolution-palingenesis interaction.
The identification of_93_day_periodic_photometric_variability_for_yso_ylw_16aSérgio Sacani
This study identifies a 93 day periodic photometric variability in the Class I young stellar object (YSO) YLW 16A in the Rho Ophiuchus star forming region. Light curve analysis reveals variations of ~0.5 magnitudes in the Ks band over this period. The authors propose a triple system model consisting of an inner binary with a 93 day period eclipsed by a warped circumbinary disk, with a tertiary companion at ~40 AU responsible for warping the disk. This model is similar to one previously proposed for another YSO, WL 4, and may indicate such triple systems with eclipsing disks are common around young stars. Understanding these systems can provide insights into stellar and planetary formation and evolution.
1) New measurements of tungsten isotopes in lunar rocks indicate that the Moon formed later than previously thought, between 62-150 million years after the formation of the solar system, challenging current models of early planetary formation.
2) This later formation of the Moon requires revising our understanding of the timing of events like the giant impact that formed the Earth-Moon system and the solidification of the lunar magma ocean.
3) The new timeline suggests Earth's core may have formed independently of the giant impact and that magma oceans on Earth and other terrestrial planets took longer to solidify than models predicted.
Modelling element abundances_in_semi_analytic_models_of_galaxy_formationSérgio Sacani
This document summarizes a new implementation of detailed chemical enrichment modeling in the Munich semi-analytic model of galaxy formation (L-Galaxies). The new implementation tracks the delayed enrichment of 11 heavy elements from stellar winds, supernovae type II, and supernovae type Ia. It considers different supernovae type II yield sets and three supernovae type Ia delay-time distributions. The results are compared to observational data on local star-forming galaxies, Milky Way disc G dwarfs, and local elliptical galaxies. Overall, the best model matches require a power-law supernovae type Ia delay-time distribution, supernovae type II yields accounting for prior mass loss, and some direct ejection
The document discusses nucleosynthesis in the early universe and provides evidence for the Big Bang theory. It explains that during the first three minutes after the Big Bang, most deuterium combined to form helium and trace amounts of lithium. The predicted abundances of these light elements depend on the density of ordinary matter and agree well with observations, providing strong evidence for the Big Bang.
The document summarizes the evolution of Earth from its formation to present day. It describes how:
- Dust and gas coalesced from the solar nebula to form planetesimals and eventually Earth around 4.5 billion years ago.
- Early Earth was mostly molten due to heavy bombardment and radioactive decay. The heat allowed the planet to differentiate into a core, mantle, and crust.
- As Earth cooled, water and an atmosphere formed. Photosynthetic life evolved and increased oxygen in the atmosphere around 2.4 billion years ago.
- Plate tectonics and volcanism have continuously recycled Earth's crust and regulated temperatures and atmospheric gases through geologic time.
Magnesium isotope evidence that accretional vapour loss shapes planetary comp...Sérgio Sacani
It has long been recognized that Earth and other differentiated
planetary bodies are chemically fractionated compared to primitive,
chondritic meteorites and, by inference, the primordial disk
from which they formed. However, it is not known whether the
notable volatile depletions of planetary bodies are a consequence
of accretion1
or inherited from prior nebular fractionation2
. The
isotopic compositions of the main constituents of planetary bodies
can contribute to this debate3–6. Here we develop an analytical
approach that corrects a major cause of measurement inaccuracy
inherent in conventional methods, and show that all differentiated
bodies have isotopically heavier magnesium compositions
than chondritic meteorites. We argue that possible magnesium
isotope fractionation during condensation of the solar nebula,
core formation and silicate differentiation cannot explain these
observations. However, isotopic fractionation between liquid and
vapour, followed by vapour escape during accretionary growth of
planetesimals, generates appropriate residual compositions. Our
modelling implies that the isotopic compositions of magnesium,
silicon and iron, and the relative abundances of the major elements
of Earth and other planetary bodies, are a natural consequence of
substantial (about 40 per cent by mass) vapour loss from growing
planetesimals by this mechanism.
This document analyzes the magnesium isotopic compositions of 22 differentiated meteorites from 7 types of achondrites and pallasite meteorites. It finds:
1) Achondrites have d26Mg values ranging from -0.369‰ to -0.158‰, with most compositions similar and showing no significant isotopic fractionation.
2) However, some angrites and howardite-eucrite-diogenite (HED) meteorites have slightly heavier Mg isotopic compositions, possibly due to impact evaporation or higher clinopyroxene abundances.
3) The average Mg isotopic composition of achondrites (-0.246‰) is indistinguish
This document discusses evidence that the Moon-forming impact occurred later than previously thought, at around 95 million years after the formation of the solar system. The study uses simulations of planetary formation to show a correlation between the timing of the last giant impact and the amount of mass later accreted by the planet. Comparing this to highly siderophile element abundances in Earth's mantle, which constrain the amount of late-accreted mass, the study determines the Moon-forming impact was most likely 95 million years after solar system formation. Earlier times of 40 million years or less are ruled out at a 99.9% confidence level. The simulations include both classical scenarios and scenarios where Jupiter and Saturn migrated inward early in the solar
Evidence for a_complex_enrichment_history_of_the_stream_from_fairall_9_sightlineSérgio Sacani
This study analyzes absorption spectra of the Magellanic Stream (MS) toward the quasar Fairall 9, obtained using the Hubble Space Telescope Cosmic Origins Spectrograph (HST/COS) and the Very Large Telescope Ultraviolet and Visible Echelle Spectrograph (VLT/UVES). The spectra reveal absorption from multiple velocity components of the MS, indicating multiphase gas. Surprisingly, the sulfur abundance is found to be high ([S/H] = -0.30), five times higher than other MS sightlines, while the nitrogen abundance is lower ([N/H] = -1.15). This points to a complex enrichment history, where the gas toward Fair
EmilyPrince-Ralby Provnance of the Moon Through the Comparison of Isotopic AbEmily Prince-Ralby
This document summarizes a study aiming to determine the origin of the Moon through high-precision isotopic analysis of titanium in terrestrial, lunar, and Martian samples. The researchers developed a method using column chromatography and mass spectrometry to precisely measure titanium isotopes. Preliminary results found lunar and terrestrial samples have identical titanium isotopic abundances within measurement precision. The researchers will now analyze titanium isotopes in Martian samples to test theories on radial mixing in the early solar system and determine if Mars retained a distinct titanium signature. This may help distinguish between models of the Moon forming from Earth or an impactor body.
This document discusses iron isotope measurements of lunar samples, including the oldest lunar rock dunite 72 415. The key points are:
1) Dunite 72 415 has a surprisingly light iron isotope composition, in contrast to other lunar samples which are enriched in heavy iron isotopes compared to Earth.
2) Additional measurements of dunite 72 415 confirm this light iron isotope signature.
3) The earliest olivine accumulation in the lunar magma ocean may have been enriched in light iron isotopes, allowing the overall iron isotope composition of the Moon to match that of Earth.
Heterogeneous delivery of silicate and metal to the Earth by large planetesimalsSérgio Sacani
After the Moon’s formation, Earth experienced a protracted bombardment by leftover planetesimals. The mass delivered during
this stage of late accretion has been estimated to be approximately 0.5% of Earth’s present mass, based on highly siderophile
element concentrations in the Earth’s mantle and the assumption that all highly siderophile elements delivered by impacts
were retained in the mantle. However, late accretion may have involved mostly large (≥ 1,500 km in diameter)—and therefore
differentiated—projectiles in which highly siderophile elements were sequestered primarily in metallic cores. Here we present
smoothed-particle hydrodynamics impact simulations that show that substantial portions of a large planetesimal’s core may
descend to the Earth’s core or escape accretion entirely. Both outcomes reduce the delivery of highly siderophile elements to
the Earth’s mantle and imply a late accretion mass that may be two to five times greater than previously thought. Further, we
demonstrate that projectile material can be concentrated within localized domains of Earth’s mantle, producing both positive
and negative 182W isotopic anomalies of the order of 10 to 100 ppm. In this scenario, some isotopic anomalies observed in terrestrial
rocks can be explained as products of collisions after Moon formation.
foundations of astronomy - the very basicsMaryPavlenko
The document provides information about the Earth and Moon. It summarizes that the Earth is differentiated with an iron core, silicate mantle and crust. The mantle flows like a liquid due to heat convection. Plate tectonics causes geological activity. Radiometric dating indicates the Earth is approximately 4.6 billion years old. The Moon has no atmosphere or magnetic field and its surface is dominated by impact craters. Evidence suggests there may be water ice at the lunar poles.
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.
One tenth solar_abundances_along_the_body_of-the_streamSérgio Sacani
This document summarizes a study that analyzed spectra from four background quasars to measure the chemical abundances along the Magellanic Stream. Two key findings are:
1) The sightlines toward RBS 144 and NGC 7714 yielded metallicities of around 0.1 times the solar value, indicating a uniform low abundance along the main body of the Stream. This supports models where the Stream was stripped from the SMC around 1-2.5 billion years ago when the SMC had a metallicity of around 0.1 solar.
2) A higher metallicity of around 0.5 solar was found in the inner Stream toward Fairall 9, sampling a filament traced to the LMC. This shows the bifurc
Hot Earth or Young Venus? A nearby transiting rocky planet mysterySérgio Sacani
Venus and Earth provide astonishingly different views of the evolution of a rocky planet, raising the question of why these two rock y worlds evolv ed so differently. The recently disco v ered transiting Super-Earth LP 890-9c (TOI-4306c, SPECULOOS-2c) is a key to the question. It circles a nearby M6V star in 8.46 d. LP890-9c receives similar flux as modern Earth, which puts it very close to the inner edge of the Habitable Zone (HZ), where models differ strongly in their prediction of how long rocky planets can hold onto their water. We model the atmosphere of a hot LP890-9c at the inner edge of the HZ, where the planet could sustain several very different environments. The resulting transmission spectra differ considerably between a hot, wet exo-Earth, a steamy planet caught in a runaway greenhouse, and an exo-Venus. Distinguishing these scenarios from the planet’s spectra will provide critical new insights into the evolution of hot terrestrial planets into exo-Venus. Our model and spectra are available online as a tool to plan observations. They show that observing LP890-9c can provide key insights into the evolution of a rocky planet at the inner edge of the HZ as well as the long-term future of Earth.
Four new planets_around_giant_stars_and_the_mass_metallicity_correlation_of_p...Sérgio Sacani
Exoplanet searches have revealed interesting correlations between the stellar properties and the occurrence rate of planets.
In particular, different independent surveys have demonstrated that giant planets are preferentially found around metal-rich stars and
that their fraction increases with the stellar mass.
Aims. During the past six years, we have conducted a radial velocity follow-up program of 166 giant stars, to detect substellar
companions, and characterizing their orbital properties. Using this information, we aim to study the role of the stellar evolution in
the orbital parameters of the companions, and to unveil possible correlations between the stellar properties and the occurrence rate of
giant planets.
Methods. We have taken multi-epoch spectra using FEROS and CHIRON for all of our targets, from which we have computed
precision radial velocities and we have derived atmospheric and physical parameters. Additionally, velocities computed from UCLES
spectra are presented here. By studying the periodic radial velocity signals, we have detected the presence of several substellar
companions.
Results. We present four new planetary systems around the giant stars HIP8541, HIP74890, HIP84056 and HIP95124. Additionally,
we study the correlation between the occurrence rate of giant planets with the stellar mass and metallicity of our targets. We find that
giant planets are more frequent around metal-rich stars, reaching a peak in the detection of f = 16.7+15.5
−5.9 % around stars with [Fe/H] ∼
0.35 dex. Similarly, we observe a positive correlation of the planet occurrence rate with the stellar mass, between M⋆∼ 1.0 - 2.1 M⊙ ,
with a maximum of f = 13.0+10.1
−4.2 %, at M⋆= 2.1 M⊙ .
Conclusions. We conclude that giant planets are preferentially formed around metal-rich stars. Also, we conclude that they are more
efficiently formed around more massive stars, in the stellar mass range of ∼ 1.0 - 2.1 M⊙ . These observational results confirm previous
findings for solar-type and post-MS hosting stars, and provide further support to the core-accretion formation model.
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
�
(
�
−
�
)
∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
000
±
2
,
000
km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
�
Ca-rich population. Although such an object is too red for any low-
�
cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
≲
1
�
) with
Λ
CDM. Therefore unlike low-
�
Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
�
truly diverge from their low-
�
counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
More Related Content
Similar to Age of Jupiter inferred from the distinct genetics and formation times of meteorites
1) New measurements of tungsten isotopes in lunar rocks indicate that the Moon formed later than previously thought, between 62-150 million years after the formation of the solar system, challenging current models of early planetary formation.
2) This later formation of the Moon requires revising our understanding of the timing of events like the giant impact that formed the Earth-Moon system and the solidification of the lunar magma ocean.
3) The new timeline suggests Earth's core may have formed independently of the giant impact and that magma oceans on Earth and other terrestrial planets took longer to solidify than models predicted.
Modelling element abundances_in_semi_analytic_models_of_galaxy_formationSérgio Sacani
This document summarizes a new implementation of detailed chemical enrichment modeling in the Munich semi-analytic model of galaxy formation (L-Galaxies). The new implementation tracks the delayed enrichment of 11 heavy elements from stellar winds, supernovae type II, and supernovae type Ia. It considers different supernovae type II yield sets and three supernovae type Ia delay-time distributions. The results are compared to observational data on local star-forming galaxies, Milky Way disc G dwarfs, and local elliptical galaxies. Overall, the best model matches require a power-law supernovae type Ia delay-time distribution, supernovae type II yields accounting for prior mass loss, and some direct ejection
The document discusses nucleosynthesis in the early universe and provides evidence for the Big Bang theory. It explains that during the first three minutes after the Big Bang, most deuterium combined to form helium and trace amounts of lithium. The predicted abundances of these light elements depend on the density of ordinary matter and agree well with observations, providing strong evidence for the Big Bang.
The document summarizes the evolution of Earth from its formation to present day. It describes how:
- Dust and gas coalesced from the solar nebula to form planetesimals and eventually Earth around 4.5 billion years ago.
- Early Earth was mostly molten due to heavy bombardment and radioactive decay. The heat allowed the planet to differentiate into a core, mantle, and crust.
- As Earth cooled, water and an atmosphere formed. Photosynthetic life evolved and increased oxygen in the atmosphere around 2.4 billion years ago.
- Plate tectonics and volcanism have continuously recycled Earth's crust and regulated temperatures and atmospheric gases through geologic time.
Magnesium isotope evidence that accretional vapour loss shapes planetary comp...Sérgio Sacani
It has long been recognized that Earth and other differentiated
planetary bodies are chemically fractionated compared to primitive,
chondritic meteorites and, by inference, the primordial disk
from which they formed. However, it is not known whether the
notable volatile depletions of planetary bodies are a consequence
of accretion1
or inherited from prior nebular fractionation2
. The
isotopic compositions of the main constituents of planetary bodies
can contribute to this debate3–6. Here we develop an analytical
approach that corrects a major cause of measurement inaccuracy
inherent in conventional methods, and show that all differentiated
bodies have isotopically heavier magnesium compositions
than chondritic meteorites. We argue that possible magnesium
isotope fractionation during condensation of the solar nebula,
core formation and silicate differentiation cannot explain these
observations. However, isotopic fractionation between liquid and
vapour, followed by vapour escape during accretionary growth of
planetesimals, generates appropriate residual compositions. Our
modelling implies that the isotopic compositions of magnesium,
silicon and iron, and the relative abundances of the major elements
of Earth and other planetary bodies, are a natural consequence of
substantial (about 40 per cent by mass) vapour loss from growing
planetesimals by this mechanism.
This document analyzes the magnesium isotopic compositions of 22 differentiated meteorites from 7 types of achondrites and pallasite meteorites. It finds:
1) Achondrites have d26Mg values ranging from -0.369‰ to -0.158‰, with most compositions similar and showing no significant isotopic fractionation.
2) However, some angrites and howardite-eucrite-diogenite (HED) meteorites have slightly heavier Mg isotopic compositions, possibly due to impact evaporation or higher clinopyroxene abundances.
3) The average Mg isotopic composition of achondrites (-0.246‰) is indistinguish
This document discusses evidence that the Moon-forming impact occurred later than previously thought, at around 95 million years after the formation of the solar system. The study uses simulations of planetary formation to show a correlation between the timing of the last giant impact and the amount of mass later accreted by the planet. Comparing this to highly siderophile element abundances in Earth's mantle, which constrain the amount of late-accreted mass, the study determines the Moon-forming impact was most likely 95 million years after solar system formation. Earlier times of 40 million years or less are ruled out at a 99.9% confidence level. The simulations include both classical scenarios and scenarios where Jupiter and Saturn migrated inward early in the solar
Evidence for a_complex_enrichment_history_of_the_stream_from_fairall_9_sightlineSérgio Sacani
This study analyzes absorption spectra of the Magellanic Stream (MS) toward the quasar Fairall 9, obtained using the Hubble Space Telescope Cosmic Origins Spectrograph (HST/COS) and the Very Large Telescope Ultraviolet and Visible Echelle Spectrograph (VLT/UVES). The spectra reveal absorption from multiple velocity components of the MS, indicating multiphase gas. Surprisingly, the sulfur abundance is found to be high ([S/H] = -0.30), five times higher than other MS sightlines, while the nitrogen abundance is lower ([N/H] = -1.15). This points to a complex enrichment history, where the gas toward Fair
EmilyPrince-Ralby Provnance of the Moon Through the Comparison of Isotopic AbEmily Prince-Ralby
This document summarizes a study aiming to determine the origin of the Moon through high-precision isotopic analysis of titanium in terrestrial, lunar, and Martian samples. The researchers developed a method using column chromatography and mass spectrometry to precisely measure titanium isotopes. Preliminary results found lunar and terrestrial samples have identical titanium isotopic abundances within measurement precision. The researchers will now analyze titanium isotopes in Martian samples to test theories on radial mixing in the early solar system and determine if Mars retained a distinct titanium signature. This may help distinguish between models of the Moon forming from Earth or an impactor body.
This document discusses iron isotope measurements of lunar samples, including the oldest lunar rock dunite 72 415. The key points are:
1) Dunite 72 415 has a surprisingly light iron isotope composition, in contrast to other lunar samples which are enriched in heavy iron isotopes compared to Earth.
2) Additional measurements of dunite 72 415 confirm this light iron isotope signature.
3) The earliest olivine accumulation in the lunar magma ocean may have been enriched in light iron isotopes, allowing the overall iron isotope composition of the Moon to match that of Earth.
Heterogeneous delivery of silicate and metal to the Earth by large planetesimalsSérgio Sacani
After the Moon’s formation, Earth experienced a protracted bombardment by leftover planetesimals. The mass delivered during
this stage of late accretion has been estimated to be approximately 0.5% of Earth’s present mass, based on highly siderophile
element concentrations in the Earth’s mantle and the assumption that all highly siderophile elements delivered by impacts
were retained in the mantle. However, late accretion may have involved mostly large (≥ 1,500 km in diameter)—and therefore
differentiated—projectiles in which highly siderophile elements were sequestered primarily in metallic cores. Here we present
smoothed-particle hydrodynamics impact simulations that show that substantial portions of a large planetesimal’s core may
descend to the Earth’s core or escape accretion entirely. Both outcomes reduce the delivery of highly siderophile elements to
the Earth’s mantle and imply a late accretion mass that may be two to five times greater than previously thought. Further, we
demonstrate that projectile material can be concentrated within localized domains of Earth’s mantle, producing both positive
and negative 182W isotopic anomalies of the order of 10 to 100 ppm. In this scenario, some isotopic anomalies observed in terrestrial
rocks can be explained as products of collisions after Moon formation.
foundations of astronomy - the very basicsMaryPavlenko
The document provides information about the Earth and Moon. It summarizes that the Earth is differentiated with an iron core, silicate mantle and crust. The mantle flows like a liquid due to heat convection. Plate tectonics causes geological activity. Radiometric dating indicates the Earth is approximately 4.6 billion years old. The Moon has no atmosphere or magnetic field and its surface is dominated by impact craters. Evidence suggests there may be water ice at the lunar poles.
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.
One tenth solar_abundances_along_the_body_of-the_streamSérgio Sacani
This document summarizes a study that analyzed spectra from four background quasars to measure the chemical abundances along the Magellanic Stream. Two key findings are:
1) The sightlines toward RBS 144 and NGC 7714 yielded metallicities of around 0.1 times the solar value, indicating a uniform low abundance along the main body of the Stream. This supports models where the Stream was stripped from the SMC around 1-2.5 billion years ago when the SMC had a metallicity of around 0.1 solar.
2) A higher metallicity of around 0.5 solar was found in the inner Stream toward Fairall 9, sampling a filament traced to the LMC. This shows the bifurc
Hot Earth or Young Venus? A nearby transiting rocky planet mysterySérgio Sacani
Venus and Earth provide astonishingly different views of the evolution of a rocky planet, raising the question of why these two rock y worlds evolv ed so differently. The recently disco v ered transiting Super-Earth LP 890-9c (TOI-4306c, SPECULOOS-2c) is a key to the question. It circles a nearby M6V star in 8.46 d. LP890-9c receives similar flux as modern Earth, which puts it very close to the inner edge of the Habitable Zone (HZ), where models differ strongly in their prediction of how long rocky planets can hold onto their water. We model the atmosphere of a hot LP890-9c at the inner edge of the HZ, where the planet could sustain several very different environments. The resulting transmission spectra differ considerably between a hot, wet exo-Earth, a steamy planet caught in a runaway greenhouse, and an exo-Venus. Distinguishing these scenarios from the planet’s spectra will provide critical new insights into the evolution of hot terrestrial planets into exo-Venus. Our model and spectra are available online as a tool to plan observations. They show that observing LP890-9c can provide key insights into the evolution of a rocky planet at the inner edge of the HZ as well as the long-term future of Earth.
Four new planets_around_giant_stars_and_the_mass_metallicity_correlation_of_p...Sérgio Sacani
Exoplanet searches have revealed interesting correlations between the stellar properties and the occurrence rate of planets.
In particular, different independent surveys have demonstrated that giant planets are preferentially found around metal-rich stars and
that their fraction increases with the stellar mass.
Aims. During the past six years, we have conducted a radial velocity follow-up program of 166 giant stars, to detect substellar
companions, and characterizing their orbital properties. Using this information, we aim to study the role of the stellar evolution in
the orbital parameters of the companions, and to unveil possible correlations between the stellar properties and the occurrence rate of
giant planets.
Methods. We have taken multi-epoch spectra using FEROS and CHIRON for all of our targets, from which we have computed
precision radial velocities and we have derived atmospheric and physical parameters. Additionally, velocities computed from UCLES
spectra are presented here. By studying the periodic radial velocity signals, we have detected the presence of several substellar
companions.
Results. We present four new planetary systems around the giant stars HIP8541, HIP74890, HIP84056 and HIP95124. Additionally,
we study the correlation between the occurrence rate of giant planets with the stellar mass and metallicity of our targets. We find that
giant planets are more frequent around metal-rich stars, reaching a peak in the detection of f = 16.7+15.5
−5.9 % around stars with [Fe/H] ∼
0.35 dex. Similarly, we observe a positive correlation of the planet occurrence rate with the stellar mass, between M⋆∼ 1.0 - 2.1 M⊙ ,
with a maximum of f = 13.0+10.1
−4.2 %, at M⋆= 2.1 M⊙ .
Conclusions. We conclude that giant planets are preferentially formed around metal-rich stars. Also, we conclude that they are more
efficiently formed around more massive stars, in the stellar mass range of ∼ 1.0 - 2.1 M⊙ . These observational results confirm previous
findings for solar-type and post-MS hosting stars, and provide further support to the core-accretion formation model.
Similar to Age of Jupiter inferred from the distinct genetics and formation times of meteorites (20)
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
�
(
�
−
�
)
∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
000
±
2
,
000
km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
�
Ca-rich population. Although such an object is too red for any low-
�
cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
≲
1
�
) with
Λ
CDM. Therefore unlike low-
�
Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
�
truly diverge from their low-
�
counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary S...Sérgio Sacani
Wereport the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the R–I spectral index by 1.0 ±0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ287 as well as the dense monitoring sample of Krakow.
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Sérgio Sacani
Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H−K and K−L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (≈15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20◦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holes– stars: formation– Galaxy: center– galaxies: star formation
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
Anti-Universe And Emergent Gravity and the Dark UniverseSérgio Sacani
Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law for entanglement entropy. The extension to de Sitter space requires taking into account the entropy and temperature associated with the cosmological horizon. Using insights from string theory, black hole physics and quantum information theory we argue that the positive dark energy leads to a thermal volume law contribution to the entropy that overtakes the area law precisely at the cosmological horizon. Due to the competition between area and volume law entanglement the microscopic de Sitter states do not thermalise at sub-Hubble scales: they exhibit memory effects in the form of an entropy displacement caused by matter. The emergent laws of gravity contain an additional ‘dark’ gravitational force describing the ‘elastic’ response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newton’s constant and the Hubble acceleration scale a0 = cH0, and provide evidence for the fact that this additional ‘dark gravity force’ explains the observed phenomena in galaxies and clusters currently attributed to dark matter.
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.
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...Scintica Instrumentation
Targeting Hsp90 and its pathogen Orthologs with Tethered Inhibitors as a Diagnostic and Therapeutic Strategy for cancer and infectious diseases with Dr. Timothy Haystead.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
PPT on Direct Seeded Rice presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
Age of Jupiter inferred from the distinct genetics and formation times of meteorites
1. Age of Jupiter inferred from the distinct genetics and
formation times of meteorites
Thomas S. Kruijera,b,1
, Christoph Burkhardta
, Gerrit Buddea
, and Thorsten Kleinea
a
Institut für Planetologie, University of Münster, 48149 Muenster, Germany; and b
Nuclear and Chemical Sciences Division, Lawrence Livermore National
Laboratory, Livermore, CA 94550
Edited by Neta A. Bahcall, Princeton University, Princeton, NJ, and approved May 4, 2017 (received for review March 23, 2017)
The age of Jupiter, the largest planet in our Solar System, is still
unknown. Gas-giant planet formation likely involved the growth
of large solid cores, followed by the accumulation of gas onto
these cores. Thus, the gas-giant cores must have formed before
dissipation of the solar nebula, which likely occurred within less
than 10 My after Solar System formation. Although such rapid
accretion of the gas-giant cores has successfully been modeled,
until now it has not been possible to date their formation. Here,
using molybdenum and tungsten isotope measurements on iron
meteorites, we demonstrate that meteorites derive from two
genetically distinct nebular reservoirs that coexisted and remained
spatially separated between ∼1 My and ∼3–4 My after Solar System
formation. The most plausible mechanism for this efficient separa-
tion is the formation of Jupiter, opening a gap in the disk and
preventing the exchange of material between the two reservoirs.
As such, our results indicate that Jupiter’s core grew to ∼20 Earth
masses within <1 My, followed by a more protracted growth to ∼50
Earth masses until at least ∼3–4 My after Solar System formation.
Thus, Jupiter is the oldest planet of the Solar System, and its solid
core formed well before the solar nebula gas dissipated, consistent
with the core accretion model for giant planet formation.
Jupiter | giant planet formation | nucleosynthetic isotope anomalies |
Hf-W chronometry | solar nebula
The formation of gas-giant planets such as Jupiter and Saturn
is thought to have involved the growth of large solid cores of
∼10–20 Earth masses (ME), followed by the accumulation of gas
onto these cores (1, 2). Thus, the gas-giant cores must have formed
before dissipation of the solar nebula—the gaseous circumstellar
disk surrounding the young Sun—which likely occurred between
1 My and 10 My after Solar System formation (3). Although such
rapid accretion of the gas-giant cores has successfully been
modeled (1, 2, 4), until now it has not been possible to actually
date their formation. Here we show that the growth of Jupiter
can be dated using the distinct genetic heritage and formation
times of meteorites.
Most meteorites derive from small bodies located in the main
asteroid belt between Mars and Jupiter. Originally these bodies
probably formed at a much wider range of heliocentric distances,
as suggested by the distinct chemical and isotopic compositions
of meteorites (5–8) and by dynamical models indicating that the
gravitational influence of the gas giants led to scattering of small
bodies into the asteroid belt (9, 10). Information on the initial
formation location of meteorite parent bodies within the solar
accretion disk can be obtained from nucleosynthetic isotope
anomalies in meteorites. These anomalies arise through the
heterogeneous distribution of isotopically anomalous presolar
components and vary as a function of heliocentric distance (6, 11).
For instance, Cr, Ti, and Mo isotope anomalies (6–8, 12) reveal a
fundamental dichotomy in the genetic heritage of meteorites,
distinguishing between “noncarbonaceous” and “carbonaceous”
meteorite reservoirs (11). This distinction may reflect either a
temporal change in disk composition or the separation of materials
accreted inside [noncarbonaceous (NC) meteorites] and outside
[carbonaceous (CC) meteorites] the orbit of Jupiter (11–14). If the
latter is correct, then the age of Jupiter can be determined by
assessing the formation time and longevity of the NC and CC
meteorite reservoirs. However, it is currently not known when
these two reservoirs formed and whether and for how long they
remained isolated from each other.
To address these issues and to ultimately determine the
timescale of Jupiter’s formation, we obtained W and Mo isotopic
data for iron meteorites (Materials and Methods, SI Materials and
Methods, Fig. S1, and Tables S1–S4). These samples are frag-
ments of the metallic cores from some of the earliest-formed
planetesimals (15), making them ideal samples to search for
the effects of giant planet formation on the dynamics of the early
Solar System. Previous W isotope studies on iron meteorites
have focused on the major groups (i.e., IIAB, IID, IIIAB, IVA,
and IVB) and on determining the timescales and processes of core
formation in these bodies (15). Here we extend these studies by
examining a larger set of iron meteorite groups (i.e., IC, IIC, IID,
IIF, IIIE, and IIIF), for which we determined the timing of core
formation using the 182
Hf–182
W chronometer (half-life = 8.9 My),
as well as nucleosynthetic Mo isotopic signatures, which enables
us to link these irons to either the NC or the CC meteorites.
CC and NC Iron Meteorites
The Mo isotopic data reveal variable nucleosynthetic anomalies
in iron meteorites (Fig. 1). Consistent with prior studies (6), we
find that these anomalies predominantly reflect the heteroge-
neous distribution of a presolar carrier enriched in Mo nuclides
produced in the slow neutron capture process (s-process) of
nucleosynthesis (Fig. 1). However, in a plot of e95
Mo vs. e94
Mo
(the parts per 10,000 deviations of 95
Mo/96
Mo and 94
Mo/96
Mo
from terrestrial standard values), the iron meteorites fall onto
Significance
Jupiter is the most massive planet of the Solar System and its
presence had an immense effect on the dynamics of the solar
accretion disk. Knowing the age of Jupiter, therefore, is key for
understanding how the Solar System evolved toward its
present-day architecture. However, although models predict
that Jupiter formed relatively early, until now, its formation
has never been dated. Here we show through isotope analyses
of meteorites that Jupiter’s solid core formed within only
∼1 My after the start of Solar System history, making it the
oldest planet. Through its rapid formation, Jupiter acted as an
effective barrier against inward transport of material across
the disk, potentially explaining why our Solar System lacks any
super-Earths.
Author contributions: T.S.K. and T.K. designed research; T.S.K. and C.B. performed re-
search; T.S.K., C.B., G.B., and T.K. analyzed data; and T.S.K., C.B., G.B., and T.K. wrote
the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
1
To whom correspondence should be addressed. Email: thomaskruijer@gmail.com.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.
1073/pnas.1704461114/-/DCSupplemental.
www.pnas.org/cgi/doi/10.1073/pnas.1704461114 PNAS Early Edition | 1 of 5
EARTH,ATMOSPHERIC,
ANDPLANETARYSCIENCES
2. two distinct s-process mixing lines. Whereas most of the newly
investigated irons (IIC, IID, IIF, and IIIF) plot on an s-process
mixing line together with carbonaceous chondrites, most of the
previously studied irons as well as the IC and IIIE irons plot on
another s-process mixing line together with ordinary chondrites,
enstatite chondrites, and the Earth’s mantle (ei
Mo = 0) (Fig. 1).
Thus, several iron meteorite groups (IIC, IID, IIF, IIIF, and
IVB) belong to the CC meteorites, whereas several other groups
(IC, IIAB, IIIAB, IIIE, and IVA) belong to the NC meteorites
(Fig. 1).
A similar genetic dichotomy is seen for W isotopes, which for
iron meteorites reveal two distinct clusters of e182
W and e183
W
(the parts per 10,000 deviations of 182
W/184
W and 183
W/184
W
from terrestrial standard values). The NC irons have e182
W
values between approximately –3.4 and –3.3 and no nucleosyn-
thetic W isotope anomalies (i.e., e183
W ∼ 0), whereas the CC
irons have e182
W values of around –3.2 and show nucleosynthetic
e183
W excesses (Fig. 2, Fig. S2, and Table S5). Note that the e182
W
values of each group were corrected for the effects of cosmic ray
exposure (Figs. S3 and S4 and Table S5), using Pt isotopes as the
neutron dosimeter (15). In addition, for the iron groups showing
183
W anomalies, the e182
W values were corrected for nucleo-
synthetic e182
W variations, by using correlated e182
W–e183
W
variations induced by nucleosynthetic isotope heterogeneities (15)
(see SI Text for details).
As variable e182
W values in iron meteorites reflect different
times of Hf/W fractionation during metal–silicate separation on
their parent bodies (15–17), the higher e182
W of the CC irons
indicates a later time of core formation (Table S5), at ∼2.2 My to
∼2.8 My, compared with the NC irons, at ∼0.3 My to ∼1.8 My
after the start of Solar System history [as defined by the for-
mation of Ca-Al–rich inclusions (CAI)]. A prior study has shown
that e182
W differences between different groups of iron mete-
orites could be due to distinct melting temperatures during core
formation, reflecting the different S contents and hence liquidus
temperatures of the cores (15). However, the NC and CC res-
ervoirs both include iron meteorite groups with similar volatile
element concentrations and, hence, presumably similar S contents.
Thus, different melting temperatures of the NC and CC parent
bodies cannot be the cause of the observed e182
W dichotomy. In-
stead, the difference in core formation times is most easily explained
by different accretion times of the CC and NC iron meteorite
parent bodies. Thermal modeling of bodies internally heated by
26
Al decay (SI Text) shows that the NC iron meteorite parent
bodies probably accreted within <0.4 My after CAI formation,
whereas the CC iron meteorite parent bodies accreted slightly
later, at 0.9+0.4
−0.2 My after CAI formation (Fig. 3). Taken together,
the Mo and W isotopic data thus indicate that accretion of CC and
NC iron meteorite parent bodies occurred not only in genetically
distinct nebular regions, but also at different times (Figs. 2 and 3).
Coexistence and Spatial Separation of CC and NC Meteorite
Reservoirs
The distinct genetic heritage and accretion times of iron mete-
orite parent bodies make it possible to constrain the formation
time and longevity of the NC and CC nebular reservoirs. Accretion
of CC iron meteorite parent bodies at ∼1 My after CAI formation
Fig. 1. Molybdenum isotope dichotomy of iron meteorite groups. Iron meteorites and chondrites define two distinct trends in e95
Mo vs. e94
Mo space,
separating a CC (blue symbols) from a NC reservoir (red symbols). Note that the two regressions (solid lines) through the iron meteorite and chondrites from
NC and CC reservoirs yield significantly different e95
Mo intercept values. Error bars denote 95% conf. limits on group mean values. Also shown are s-process
and r-process mixing lines (dashed lines), plotted at an ordinate e95
Mo of +0.3 and calculated using the Mo isotopic composition of presolar SiC grains (37),
representing s-process Mo and the corresponding r-process residuals. Note that other Mo isotopes show consistent systematics (Fig. S5). Data for IC, IIC, IID, IIF,
IIIF, and IIIE iron meteorites are from this study and data for chondrites and other iron meteorite groups are from ref. 6.
0 0.2 0.4 0.6
182
W
183
W
IC
IIAB
IIIAB
IIIF
IICIVBIIF
IID
IIIE
IVA
Wiley
tCAI(My)
0
1
2
3
4
'Carbonaceous'
iron meteorite groups
'Non-carbonaceous'
iron meteorite groups
Fig. 2. Tungsten isotope dichotomy of iron meteorite groups. Error bars
denote 95% conf. intervals on group mean values. e182
W signatures were
corrected for effects of nucleosynthetic heterogeneity and secondary neutron
capture (SI Text). Plotted on the right ordinate axis are two-stage Hf-W model
ages of core formation (see SI Text for details). See Fig. 1 for symbol legend.
2 of 5 | www.pnas.org/cgi/doi/10.1073/pnas.1704461114 Kruijer et al.
3. implies that by this time, the NC and CC reservoirs were already
separated. The distinction between the NC and CC reservoirs most
likely reflects the addition of presolar material enriched in r-pro-
cess nuclides to the solar nebula region from which the CC me-
teorites derive (12). Given that all CC meteorites plot on a single
s-process mixing line with a constant offset compared with the NC
line (Fig. 1), they all have the same r-process excess relative to the
NC meteorites. Consequently, this r-process component must have
been added to and homogeneously distributed within the CC
reservoir before the first CC bodies formed. The 182
W data for the
CC irons, therefore, indicate that this addition of material and,
hence, the formation of the CC reservoir occurred within ∼1 My
of Solar System formation.
A key constraint from our results is that the accretion of or-
dinary chondrite parent bodies in the NC reservoir (i.e., at
∼2 My) (18) occurred after the accretion of iron meteorite
parent bodies in the CC reservoir (at ∼1 My). Thus, the existence
of the NC and CC reservoirs cannot simply reflect a composi-
tional change of the solar nebula over time. Instead, the CC and
NC nebular reservoirs must have existed contemporaneously
and remained spatially separated within the solar circumstellar
disk. The timespan over which this separation persisted can be
inferred by considering the accretion times of the youngest
meteorite parent bodies in each reservoir. This is because in the
e95
Mo–e94
Mo diagram (Fig. 1), no meteorites plot between the
CC and NC lines, meaning that the NC and CC reservoirs cannot
have mixed but instead must have remained isolated from each
other until parent body accretion in the NC and CC reservoirs
terminated. As accretion of chondrite parent bodies occurred at
∼2 My after CAI formation in the NC reservoir (ordinary
chondrites) and until ∼3–4 My in the CC reservoir (CC chon-
drites) (18–20), this means that the NC and CC reservoirs must
have remained isolated from each other from <1 My until at
least ∼3–4 My after CAI formation. This prolonged spatial
separation of the NC and CC reservoirs cannot simply reflect a
large distance between these reservoirs within the disk, because
the rapid speed of grain drift in the disk would have facilitated
efficient mixing on much shorter timescales (21, 22). One way
to avoid the inward drift of material would be the rapid accu-
mulation of these grains into planetesimals. However, this also
cannot explain the efficient separation of the NC and CC
reservoirs, because in both reservoirs planetesimal accretion
occurred concurrently for several million years. Consequently,
the precursor dust of planetesimals in both reservoirs must have
been present for this period and, therefore, cannot have been
locked up in earlier-formed planetesimals.
The most plausible mechanism to efficiently separate two disk
reservoirs for an extended period is the accretion of a giant
planet in between them, generating a gap within the disk and
inhibiting the inward drift of dust grains (13, 23, 24) (Fig. 4).
Being the largest and nearest gas-giant planet, Jupiter is the most
likely candidate for separating the NC and CC reservoirs. As the
Earth is part of the NC reservoir, this implies that the CC res-
ervoir was initially located outside Jupiter’s orbit, meaning that
CC bodies originally derive from the outer Solar System. Be-
cause the CC meteorites include some iron meteorites, one im-
portant implication of our data is that early and rapid formation
of differentiated planetesimals was possible not only in the inner-
most terrestrial planet region (25), but also farther out in the disk.
The formation of Jupiter between the NC and CC reservoirs
not only provides a mechanism for efficiently separating these
two reservoirs for an extended period, but also provides a means
for the later transport of CC bodies into the inner Solar System.
This is necessary because although the NC and CC bodies ini-
tially formed in spatially distinct areas of the disk, at the present
day they both reside in the main asteroid belt. This is a natural
outcome of the growth of Jupiter, which ultimately leads to
scattering of bodies from beyond Jupiter’s orbit (i.e., CC bodies)
into the inner Solar System, either during an inward-then-outward
migration of Jupiter (10, 23) or during runaway growth of Jupiter
on a fixed orbit (26). Thus, the presence of Jupiter between the NC
and CC reservoirs provides the most plausible mechanism to
Fig. 4. Four snapshots of Jupiter’s growth in the solar circumstellar disk. At
stage 1, within <0.4 My after CAI, the NC iron meteorite parent bodies (red
solid symbols) accreted in a continuous gas disk characterized by inward
drag of solids. At stage 2, around ∼1 My after CAI, iron meteorite parent
bodies of the CC reservoir (blue solid symbols) had accreted and Jupiter had
already grown to ∼20 ME, preventing any inward drag of solids (24). At stage
3, from ∼2 My to ∼4 My after CAI, Jupiter grew further through gas accre-
tion onto its core. Moreover, the ordinary chondrite parent bodies (red open
symbols) accreted in the NC reservoir and CC chondrite parent bodies (blue
open symbols) in the CC reservoir. At stage 4, after ∼3–4 My after CAI, Jupiter
had grown to ∼50 ME and had opened a gap in the disk (13, 23, 24), likely
resulting in the inward migration of Jupiter. Solid boxes (Left) show the
accretion ages of iron meteorite and chondrite parent bodies in the NC and
CC reservoirs (see CC and NC Iron Meteorites).
Fig. 3. Relation between the time of accretion and core formation on iron
meteorite parent bodies. Curves show thermal modeling results quantifying
the relation between the time of core formation and the time of parent
body accretion (SI Text), for different Al concentrations of the bulk parent
bodies (for 8.65 wt%, 12 wt%, and 16.8 wt% Al). Colored areas show the
observed core formation ages of NC iron meteorite parent bodies and CC
parent bodies.
Kruijer et al. PNAS Early Edition | 3 of 5
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4. account for both (i) the prolonged spatial separation of these
reservoirs and (ii) the co-occurrence of NC and CC bodies in the
present-day asteroid belt.
Growth History of Jupiter
With the assumption that the prolonged spatial separation of the
NC and CC reservoirs reflects the formation of Jupiter in be-
tween these reservoirs, the distinct timescales for the accretion of
NC and CC meteorite parent bodies make it possible to date the
formation of Jupiter. The growth of Jupiter beyond a certain mass
would have inhibited the inward drift of particles (13, 24), and once
it grew further, Jupiter ultimately would have generated a gap
within the disk (23). In particular, theoretical studies suggest that
the inward drift of particles stopped once Jupiter’s core had grown
to about 20 ME (24), while a gap formed once Jupiter reached
approximately 50 ME (13, 23, 27). Thus, because the r-process ma-
terial that was added to the CC reservoir did not infiltrate the
coexisting yet spatially separated NC reservoir, this implies that at
the time the r-process material was added, Jupiter already had a size
of >20 ME. Furthermore, because this material must have been
added and homogenized before the first planetesimals formed within
the CC reservoir at ∼1 My after CAI formation, these results
mandate that Jupiter reached a size of >20 ME within ∼1 My of
Solar System formation (Fig. 4). This early formation of (proto-)
Jupiter is consistent with the rapid growth of Jupiter’s core predicted
in theoretical models (1, 4), regardless of whether pebble accre-
tion (28, 29) or hierarchical growth models (30, 31) are assumed.
Once Jupiter reached a mass of 50 ME, which happens via gas
accretion onto its solid core, a gap opened in the disk (13, 23, 24,
27), followed by scattering of bodies from beyond Jupiter’s orbit
(i.e., CC bodies) into the inner Solar System (10, 23, 26). Our
results show that this scattering of CC bodies and, hence,
Jupiter’s outward migration or runaway growth cannot have
started before ∼3–4 My after CAI formation. This is because CC
chondrite parent bodies continued to form until at least ∼3–4 My
after CAI formation (18–20). As these chondrites plot on the CC
line in Mo isotope space (Fig. 1), they must have formed before
the scattering of CC meteorites into the inner Solar System and,
hence, before the CC meteorite parent bodies joined the NC
parent bodies in the asteroid belt. Accordingly, these data in-
dicate that Jupiter reached ∼50 ME later than ∼3–4 My after
CAI formation. This is consistent with theoretical predictions
that the rapid growth of Jupiter’s core to ∼20 ME was followed by
a more protracted stage of gas and solid accretion to several tens
of Earth’s masses (1, 32, 33) before runaway gas accretion led to
Jupiter’s final mass (∼318 ME). Thus, our results are in good
agreement with the timing and sequence of events predicted in
the core accretion model for the formation of Jupiter (1). One
important implication of this result is that, because Jupiter acted
as a barrier against inward transport of solids across the disk, the
inner Solar System remained relatively mass deficient, possibly
explaining its lack of any “super-Earths” (34, 35).
Materials and Methods
For this study we selected a total of 19 samples covering six different rare iron
meteorite groups (IC, IIC, IID, IIF, IIIE, and IIIF). This sample set complements
the iron meteorites from major groups (IIAB, IID, IIIAB, IVA, and IVB) whose W,
Pt, and Mo isotope compositions had previously been analyzed (6, 15). After
digestion of the iron meteorites in concentrated HNO3–HCl (2:1), the sample
solutions were split into a fraction for W and Mo (∼90%) and for Pt (∼10%)
isotope analysis. The chemical separation of W, Pt, and Mo was accom-
plished using ion exchange chromatography following previously published
procedures (6, 12, 15, 36). The W, Pt, and Mo isotope compositions were
measured on a ThermoScientific Neptune Plus MC-ICPMS in the Institut für
Planetologie at the University of Münster (12, 15, 36) (see SI Materials and
Methods for details). Instrumental mass bias was corrected by internally
normalizing to 186
W/184
W = 0.92767, 198
Pt/195
Pt = 0.2145, and 98
Mo/96
Mo =
1.453173, using the exponential law. The W, Pt, and Mo isotope data are
reported as e-unit (i.e., parts per 104
) deviation relative to the isotopic ratios
measured for terrestrial bracketing solution standards. The reported ei
W,
ei
Pt, and ei
Mo values for samples (Tables S1–S4) represent the mean of
pooled solution replicates (n = 1–8) together with their associated uncertainties
[2 SD or 95% confidence (conf.) interval].
ACKNOWLEDGMENTS. We gratefully acknowledge the Natural History
Museum, London (C. Smith, N. Almeida) and the Field Museum, Chicago
(P. Heck) for providing samples. We thank F. Nimmo for giving detailed
insights into giant planet formation and for a first draft of Fig. 4. We also
thank G. Brennecka and A. Morbidelli for discussions; C. Brennecka for com-
ments on the paper; and S. Gerber, J. Hellmann, N. Krabbe, and U. Heitmann
for their assistance. Finally, we thank Alex Halliday and two anonymous
reviewers for their constructive comments that helped to improve the paper.
This study was performed under the auspices of the US DOE by Lawrence
Livermore National Laboratory under Contract DE-AC52-07NA27344 with
release number LLNL-JRNL-731226. This work was funded by the Deutsche
Forschungsgemeinschaft (DFG) (Collaborative Research Center/Transregio
TRR 170 subproject B3-1). C.B. was supported by the European Research Coun-
cil Consolidator grant ISOCORE (Contract 616564), and G.B. was supported by
the DFG Priority Program 1385 (Grant KL1857/3). This is TRR 170 publication 10.
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