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Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
Extrasolar planets
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Extrasolar planets
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Extrasolar planets

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  • 1. Exoplanets Monday, March 31, 2014
  • 2. • Review Planet Formation Theory • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 3. • Review Planet Formation Theory • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 4. • Review Planet Formation Theory • Snowline • Core Accretion • Migration • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 5. • Review Planet Formation Theory • Snowline • Core Accretion • Migration • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 6. Water Rock IronMethane Monday, March 31, 2014
  • 7. Monday, March 31, 2014
  • 8. 10 Marcy, Butler, Fischer, Vogt, Wright, Tinney and Jones Fig. 6. The occurrence of exoplanets vs iron abundance [Fe/H] of the host star measured spectro- scopically.21) The occurrence of observed giant planets increases strongly with stellar metal- licity. The solid line is a power law fit for the probability that a star has a detected planet: P(planet) = 0.03 × 102.0×[Fe/H] Monday, March 31, 2014
  • 9. • Review Planet Formation Theory: • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock & iron. • Core Accretion • Migration • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 10. • Review Planet Formation Theory: • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock & iron. • Core Accretion • Migration • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 11. 2 Mordasini et al. Figure 1. Time evolution of the mass of accreted planetesimals (solid line), the mass of accreted gas (dotted line) and total mass of the planet (dashed line), for initial conditions equivalent to the preferred model for the formation of Jupiter in Pollack et al. (1996) (from Alibert et al. 2005a). Monday, March 31, 2014
  • 12. Fig. 4.—Time evolution of core mass (105, 106, and 107 yr), shown by sold lines, in the case of (a) fd ¼ 1 and (b) fd ¼ 10. Core mass is truncated by Mc;iso (top panels) or by Mc;no iso (bottom panels), which are shown by the dashed lines. The jumps at 2.7 AU are caused by increase in solid materials due to ice condensation. IDA & LIN396 Vol. 604 Monday, March 31, 2014
  • 13. appropriate upper limit for masses of gas giants (Bryden et al. 1999). weakened by the growth through giant impacts after the disk depletion. The truncation conditions of the cores and gas do Fig. 9.—Theoretically predicted distribution based on the core accretion model for gas giant planets (for the range of parameters we used, see text). Cores are truncated by Mc;iso. Gas accretion is truncated by (a) Mg;iso, (b and c) Mg;th, and (d) Mg;vis. We adopt Áag ¼ 2rH in (a), the critical Hill radius rH;c being h and 1.5h in (b) and (c), respectively, and ¼ 10À3 in (d). The green filled circles and the blue crosses represent rocky and icy planets with gaseous envelopes less massive than their cores. The green and blue open circles represent gas-rich rocky and icy planets with gaseous envelopes that are 1–10 times more massive than their cores. The red filled circles represent gas giants with envelopes more massive than 10 times their cores. For comparison, we also plot observational data of extrasolar planets in (d). The dashed ascending lines correspond to radial velocity amplitude of 100 (upper line), 10 (middle line), and 1 m sÀ1 (lower line), assuming that the host star mass is 1 M. IDA LIN404 Vol. 604 • Core Accretion Monday, March 31, 2014
  • 14. • Review Planet Formation Theory: • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Migration • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 15. • Review Planet Formation Theory: • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Migration • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 16. Monday, March 31, 2014
  • 17. over a greater radial extent and the inward migration accelerates with time. In all figures, we indicate the evolution of R with asymptotic semimajor axis that is greater than 0.9 times that of their initial semimajor axis a . Since planets that form with Fig. 11.—Planetary migration obtained by integrating ˙ap with eqs. (65) and (68), shown by solid lines. Inside the thick dashed lines, final semimajor axes reach 0.04 AU. They are greater than 0.9 times their original locations, outside the thick solid lines. Dashed lines express Rm. Time is scaled by mig at 1 AU (mig;1). IDA LIN408 Vol. 604 Monday, March 31, 2014
  • 18. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 19. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • What has been learned about exoplanets Monday, March 31, 2014
  • 20. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity • Transits • Microlensing • What has been learned about exoplanets Monday, March 31, 2014
  • 21. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity • Transits • Microlensing • What has been learned about exoplanets Monday, March 31, 2014
  • 22. Newton’s Third Law • For every force, there is an equal and opposite force • If I push on you, you push on me • If the Sun pulls on Jupiter, then Jupiter pulls on the Sun Monday, March 31, 2014
  • 23. Monday, March 31, 2014
  • 24. The wobble of stars can be used to measure the mass of their planets • We used the motion of Jupiter to measure the force that the Sun exerts on Jupiter to measure the mass of the Sun. • We can use the (much smaller) motion of the Sun to measure the force that Jupiter exerts on the Sun to measure the mass of Jupiter. Monday, March 31, 2014
  • 25. Doppler Shift Monday, March 31, 2014
  • 26. Data from binary star, not a planet, just to illustrate the effect. The wobble from a planet is much smaller. Monday, March 31, 2014
  • 27. Monday, March 31, 2014
  • 28. Monday, March 31, 2014
  • 29. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity: Incredibly precise spectrograph on very apparently bright (e.g., nearby) stars measures the mass and orbital parameters of planets. Mass depends on (unknown) inclination. • Transits • Microlensing • What has been learned about exoplanets Monday, March 31, 2014
  • 30. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity: Incredibly precise spectrograph on very apparently bright (e.g., nearby) stars measures the mass and orbital parameters of planets. • Transits • Microlensing • What has been learned about exoplanets Monday, March 31, 2014
  • 31. Transit ofVenus Monday, March 31, 2014
  • 32. is capable of detecting a change in a star’s brightness equal to 20 ppm for stars that are more than spots and other variations in the brightness of a star do not repeat consistently, especially over Actual H-alpha image of the sun on the left, with a Jupiter transit superimposed to scale, as if viewed from outside our solar system. The image of the sun on the right shows an Earth transit to scale. is capable of detecting a change in a star’s brightness equal to 20 ppm for stars that are more than spots and other variations in the brightness of a star do not repeat consistently, especially over Actual H-alpha image of the sun on the left, with a Jupiter transit superimposed to scale, as if viewed from outside our solar system. The image of the sun on the right shows an Earth transit to scale. Its easier to find big planets than small planets with transits Monday, March 31, 2014
  • 33. Transits can only find close-in planets Monday, March 31, 2014
  • 34. Transits can only find close-in planets or edge on systems Monday, March 31, 2014
  • 35. Monday, March 31, 2014
  • 36. FIG. 2.ÈTime series of the corrected intensity shown separately for each of the four transits observed by HST , with successive transits o†set by [0.006 for clarity. Note that, because the transit duration is almost two HST orbits, complete temporal coverage was not obtained for any one transit. u es ab va p p th it p th as m af ^ th C D o el P isMonday, March 31, 2014
  • 37. Monday, March 31, 2014
  • 38. -0.4 -0.2 0.0 0.2 0.4 Phase 0.99 1.00 1.01 1.08 1.10 nt HAO UT 2012-02-20 Monday, March 31, 2014
  • 39. Monday, March 31, 2014
  • 40. Science data storage: about 2 months Focal Plane Radiator Sunshade 55º solar avoidance Primary Mirror 1.4 m dia, ULE Mounting Collet Focal Plane: 42 CCDs, 100 sq deq FOV 4 Fine Guidance Sensors Local Detector Electronics: clock drivers and analog to digital converters Schmidt Corrector with 0.95 m dia aperture stop (Fused Silica) Graphite Metering Structure -Upper Housing -Lower Housing -Aft Bulkhead Optical Axis Monday, March 31, 2014
  • 41. guidance CCDs in the corners. Monday, March 31, 2014
  • 42. faint for Kepler to observe the transits needed to detect Earth-size planets. The Kepler Field of View Monday, March 31, 2014
  • 43. Monday, March 31, 2014
  • 44. Monday, March 31, 2014
  • 45. Monday, March 31, 2014
  • 46. interiors of these planets, inflating their radii, and possibly pertur ing other aspects of their interior structure, in ways that we do n understand. One possibility that is currently the subject of debate Transit Gravitational tug of unseen planets alters transit times See thermal radiation from planet disappear and reappear Measure size of transiting planet, see radiation from star transmitted through the planet’s atmosphere Eclipse Figure 2 | Geometry and science yield from transiting planets. During transit, the fraction of stellar light blocked by the planet (shown black), together with the detailed shape of the transit curve, yields the radius of boMonday, March 31, 2014
  • 47. and heated olecules H2, CO and/or ost spectro- d to be the here. Some cm2 g–1 cm2 g–1 35 cm2 g–1 20 30 0.97 0.98 0.99 1.00 1.01 Relativeflux –0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 Orbital phase 0.999 1.000 1.001 1.002 1.003 Relativeflux a b Monday, March 31, 2014
  • 48. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity: Incredibly precise spectrograph on very apparently bright (e.g., nearby) stars measures the mass and orbital parameters of planets. • Transits: Incredibly precise photometry measures the size and period. • Microlensing • What has been learned about exoplanets Monday, March 31, 2014
  • 49. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity: Incredibly precise spectrograph on very apparently bright (e.g., nearby) stars measures the mass and orbital parameters of planets. • Transits: Incredibly precise photometry measures the size and period. • Microlensing • What has been learned about exoplanets Monday, March 31, 2014
  • 50. DISCUSSION LENS-L1KE OF A STAR BY THE DEVIATION OF LIGHT IN THE GRAVITATIONAL FIELD SOMEtime ago, R. W. Mandl paid me a visit and asked me to publish the results of a little calculation, which I had made at his request. This note complies with his wish. The light coming from a star A traverses the gravi- tational field of another star B, whose radius is R,. ~~t there be an observer at a distance D from B and at a distance z, small with D, from the ex- tended central line =. According to the general theory of relativity, let a, be the deviation of the light ray passing the star B at a distance R, from its center. -the sake let us assume that AB is large, with the distance the not decrease like 1/D, but like 1 / ~ 5 ,as the distance D increases. Of course, there is no hope of observing this phe- nomenon directly. First, we shall scarcely ever ap- proach closely enough to such a central line. Second, the angle 6 will defy the resolving power of our instruments. For, a, being of the order of magnitude of One second of arc, the angle Bo/D, under which the deviating star B is seen, is much smaller. Therefore, the light coming from the luminous circle can not be distinguished by an observer as geometrically different from that coming from the star B, but simply will manifest itself as increased apparent brightness of B. The same will happen, if the observer is situated* a small distance x from the extended central line AB. But then the observer will see A as two point-like light-sources, which are deviated from the true gee- from the deviating star Be We also neglect the ecli~se metrical position of A by the angle @, approximately. (geometrical obscuration) by the star B, which indeed is negligible in all practically important cases. To permit this, has to be Very large the radius Ro of the deviating star. It follows from the law of deviation that an observer situated exactly on the extension of the central line -AB will perceive, instead of a point-like star A, a luminius circle of the angular radius @ around the center of B, where It should be noted that this angular diameter 6 does The apparent brightness of A will be increased by the lcns-like of the gravitational field of B in the ,,tio q. This Will be considerably larger than unity only if x is so small that the observed positions of A and coincide, within the resolving power our instruments. geometric lead to the expression x2 1-!- I q=-.- 21 where ALBERT EINSTEIN INSTITUTE FOR ADVANCED STUDY PRINCETON, N.J. Science, 1936 Monday, March 31, 2014
  • 51. DISCUSSION LENS-L1KE OF A STAR BY THE DEVIATION OF LIGHT IN THE GRAVITATIONAL FIELD SOMEtime ago, R. W. Mandl paid me a visit and asked me to publish the results of a little calculation, which I had made at his request. This note complies with his wish. The light coming from a star A traverses the gravi- tational field of another star B, whose radius is R,. ~~t there be an observer at a distance D from B and at a distance z, small with D, from the ex- tended central line =. According to the general theory of relativity, let a, be the deviation of the light ray passing the star B at a distance R, from its center. -the sake let us assume that AB is large, with the distance the not decrease like 1/D, but like 1 / ~ 5 ,as the distance D increases. Of course, there is no hope of observing this phe- nomenon directly. First, we shall scarcely ever ap- proach closely enough to such a central line. Second, the angle 6 will defy the resolving power of our instruments. For, a, being of the order of magnitude of One second of arc, the angle Bo/D, under which the deviating star B is seen, is much smaller. Therefore, the light coming from the luminous circle can not be distinguished by an observer as geometrically different from that coming from the star B, but simply will manifest itself as increased apparent brightness of B. The same will happen, if the observer is situated* a small distance x from the extended central line AB. But then the observer will see A as two point-like light-sources, which are deviated from the true gee- from the deviating star Be We also neglect the ecli~se metrical position of A by the angle @, approximately. (geometrical obscuration) by the star B, which indeed is negligible in all practically important cases. To permit this, has to be Very large the radius Ro of the deviating star. It follows from the law of deviation that an observer situated exactly on the extension of the central line -AB will perceive, instead of a point-like star A, a luminius circle of the angular radius @ around the center of B, where It should be noted that this angular diameter 6 does The apparent brightness of A will be increased by the lcns-like of the gravitational field of B in the ,,tio q. This Will be considerably larger than unity only if x is so small that the observed positions of A and coincide, within the resolving power our instruments. geometric lead to the expression x2 1-!- I q=-.- 21 where Of course, there is no hope of observing this phenomenon directly. ALBERT EINSTEIN INSTITUTE FOR ADVANCED STUDY PRINCETON, N.J. Science, 1936 Monday, March 31, 2014
  • 52. Monday, March 31, 2014
  • 53. Monday, March 31, 2014
  • 54. Scott Gaudi, OSU Monday, March 31, 2014
  • 55. Scott Gaudi, OSU Monday, March 31, 2014
  • 56. Scott Gaudi, OSU Monday, March 31, 2014
  • 57. 3440 3460 3480 3500 20 19 18 17 16 15 HJD - 2450000 and so no non duct a Howev ensure ramete The of the peak o nitudes source- that th tral cau the “ce tral ca are ma 2005), is very only be over, tw caused are hig first peMonday, March 31, 2014
  • 58. Monday, March 31, 2014
  • 59. Jennie McCormick Housewife Amateur Astronomer Co-discoverer of over 20 planets Monday, March 31, 2014
  • 60. Meade LX200 ACF 14”f/10 Monday, March 31, 2014
  • 61. tE , 2 days, the ten observed events are well above the model predic- tions. The power-law and log-normal models predict 1.5 and 2.5 events with tE , 2 days, respectively, and the corresponding Poisson probabilities for the ten observed events are 43 1026 and 3 3 1024 . stars and brown dwarfs24 , and found that the resultant planetary-mass function parameters are consistent with the above values (see the Supplementary Information). Thelensesfortheseshorteventscouldbeeitherfree-floatingplanetsor 4,290 3,900 4,000 4,100 4,200 4,300 MOA OGLE 4,400 MOA–ip–3 tE = 1.88 u0 = 0.911 4,292 4,294 JD – 2,450,000 4,296 4,298 4,300 –0.1 0 ΔA 0.1 1 Magnification 1.4 1.2 1 Magnification 1.4 1.2 3,931 4,000 4,100 4,200 MOA 4,300 4,400 MOA–ip–10 tE = 1.19 u0 = 0.032 3,932 3,900 3,933 3,934 JD – 2,450,000 –0.2 0.2 ΔA 30 20 MagnificationMagnification 0 0 10 0 10 20 30 a b Figure 1 | Light curves of event MOA-ip-3 and event MOA-ip-10. These have the highest signal-to-noise ratio of the ten microlensing events with tE , 2 days (see Supplementary Fig. 1 for the others). MOA data are in black and OGLE data are in red, with error bars indicating the s.e.m. a, MOA-ip-3 light curve; b, MOA-ip-10 light curve. The green lines represent the best-fit microlensing model light curves. For each event, the upper panel shows the full two-year light curve, the middle panel is a close-up of the light-curve peak, and the bottom panel shows the residuals from the best-fit model in units of the magnification, DA. u0 indicates the source–lens impact parameter in units of the Einstein radius. The second phase of MOA, MOA-II, carried out a very- high-cadence photometric survey of 50 million stars in 22 bulge fields (of 2.2deg2 each) with a 1.8-m telescope at Mt John Observatory in New Zealand. MOA detects 500–600 microlensing events during eight months observation every year. In 2006–2007, MOA observed two central bulge fields every 10 min, and other bulge fields with a 50 min cadence, which resulted in about 8,250 and 1,660–2,980 images, respectively. This strategy enabled MOA to detect very short events with tE , 2 days. Since 2002, the OGLE-III survey has monitored the bulge with the 1.3-m Warsaw telescope at Las Campanas Observatory, Chile, with a smaller field-of-view but better astronomical seeing than MOA. The OGLE-III observing cadence was 1–2 observations per night, but the OGLE photometry is usually more precise and fills gaps in the MOA light curves owing to the difference in longitude. RESEARCH LETTER Monday, March 31, 2014
  • 62. Monday, March 31, 2014
  • 63. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity: Incredibly precise spectrograph on very apparently bright (e.g., nearby) stars measures the mass and orbital parameters of planets. • Transits: Incredibly precise photometry measures the size and period. • Microlensing:Able to find planets we can’t see around very distant stars, especially at the Einstein Radius. • What has been learned about exoplanets Monday, March 31, 2014
  • 64. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity: Incredibly precise spectrograph on very apparently bright (e.g., nearby) stars measures the mass and orbital parameters of planets. • Transits: Incredibly precise photometry measures the size and period. • Microlensing:Able to find planets we can’t see around very distant stars, especially at the Einstein Radius. • What has been learned about exoplanets Monday, March 31, 2014
  • 65. Monday, March 31, 2014
  • 66. 1990 1995 2000 2005 2010 10 3 100 10 First Publication Date DistancetoStar[Parsecs] exoplanets.org | 3/27/2014 Monday, March 31, 2014
  • 67. 1990 1995 2000 2005 2010 10 4 10 3 100 10 1 0.1 0.01 First Publication Date PlanetMass[EarthMass] exoplanets.org | 3/28/2014 Monday, March 31, 2014
  • 68. NASA eyes app Monday, March 31, 2014
  • 69. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity: Incredibly precise spectrograph on very apparently bright (e.g., nearby) stars measures the mass and orbital parameters of planets. • Transits: Incredibly precise photometry measures the size and period. • Microlensing:Able to find planets we can’t see around very distant stars, especially at the Einstein Radius. • What has been learned about exoplanets Monday, March 31, 2014
  • 70. • Review Planet Formation Theory: • Core Accretion: solid parts of planets glom quickly. If core gets large enough, can start to attract gas. If enough gas is attracted, planet mass can run away. • Snowline: Easier to form giants in outer solar system. Outer planets mostly water, inner planets mostly rock iron. • Migration: if disk is massive and long-lived, planets will exchange energy and angular momentum with disk and move inwards. • How are exoplanets discovered • RadialVelocity: Incredibly precise spectrograph on very apparently bright (e.g., nearby) stars measures the mass and orbital parameters of planets. • Transits: Incredibly precise photometry measures the size and period. • Microlensing:Able to find planets we can’t see around very distant stars, especially at the Einstein Radius. • What has been learned about exoplanets Monday, March 31, 2014
  • 71. Monday, March 31, 2014
  • 72. Rep. Prog. Phys. 73 (2010) 016901 Figure 9. Planetary radii at 4.5 Gyr as a function of mass, from 0.1M⊕ to 20MJup. Models with solar metallicity (Z = 2%) and with different amounts of heavy material (water, rock or iron) are shown (Models from [19, 78]). The ‘rock’ composition here is olivine or dunite, i.e. Mg SiO . Solid lines are for non-irradiated models. the behavior of the mass–radius rel Jupiter-like planets. The essential ph shape of the relation was described in Two competitive effects yield the the M–R relationship around a few regime, down to Earth masses, th contribution from the classical ion M+1/3 , characteristic of incompress density increase, the effects of part start to dominate over Coulomb effe the M–R relation. Consequently, at a critical mass which depends o Reference [62] found a critical mass to a maximum radius of ∼1RJup, f under the assumption of zero-tem recent calculations, based on impro section 4.1, yield a critical mass ∼3 Figure 9 also illustrates the incr on the planetary radius as mass decr a substantial atmosphere (see secti 20M⊕ planet with 50% H2O is enhan by a Sun at 0.045 AU [19]. For terr radius relationship, derived from d the same complex composition as Rep. Prog. Phys. 73 (2010) 016901 Figure 9. Planetary radii at 4.5 Gyr as a function of mass, from 0.1M⊕ to 20MJup. Models with solar metallicity (Z = 2%) and with different amounts of heavy material (water, rock or iron) are shown (Models from [19, 78]). The ‘rock’ composition here is olivine or dunite, i.e. Mg2SiO4. Solid lines are for non-irradiated models. Dash–dotted curves correspond to irradiated models at 0.045 AU from a Sun. The long-dashed curve, between 0.1M⊕ and 10M⊕, is the mass–radius relationship for terrestrial planets, with detailed structures and compositions characteristic of the Earth, after [76]. The positions of Mars, the Earth, Uranus, Neptune, Saturn and Jupiter are indicated by solid points. Note that pure heavy material planets (water, rock, iron) with masses 100M⊕ are unrealistic and are only shown for illustrative purposes. of models, covering a wide range of masses, including the Jupi shap Two the regi con M+1 den star the at a Ref to a und rece sect on t a su 20M by a radi the sect As d clos 100 mea thus exo on t of wMonday, March 31, 2014
  • 73. I Baraffe et al s a function Figure 2. Mass–radius diagram for transiting planets. The positionsMonday, March 31, 2014
  • 74. 1010.10.0110 -3 10 -4 PlanetMass[JupiterMass] 1 10 100 1 0.1 Orbital Period [Days] PlanetaryRadius[JupiterRadii] exoplanets.org | 3/28/2014 Monday, March 31, 2014
  • 75. Monday, March 31, 2014
  • 76. 1 10 100 10 3 10 4 100 10 1 0.1 Planet Mass [Earth Mass] PlanetaryDensity[Grams/Centimeters 3 ] exoplanets.org | 3/27/2014 Monday, March 31, 2014
  • 77. Monday, March 31, 2014
  • 78. v:1302.2147v3[astro-ph.EP]21May2013 Mon. Not. R. Astron. Soc. 000, 000–000 (0000) Printed 22 May 2013 (MN LATEX style file v2.2) Catastrophic Evaporation of Rocky Planets Daniel Perez-Becker1 and Eugene Chiang2 1 Department of Physics, University of California at Berkeley, 366 LeConte Hall, Berkeley CA 94720-7300, USA 2 Departments of Astronomy and of Earth and Planetary Science, University of California at Berkeley, Hearst Field Annex B-20, Berkeley CA 94720-3411, USA Submitted: 22 May 2013 ABSTRACT Short-period exoplanets can have dayside surface temperatures surpassing 2000 K, hot enough to vaporize rock and drive a thermal wind. Small enough planets evaporate completely. We construct a radiative-hydrodynamic model of atmospheric escape from strongly irradiated, low-mass rocky planets, accounting for dust-gas energy exchange in the wind. Rocky planets with masses 0.1M⊕ (less than twice the mass of Mercury) and surface temperatures 2000 K are found to disintegrate entirely in 10 Gyr. When our model is applied to Kepler planet candidate KIC 12557548b — which is believed to be a rocky body evaporating at a rate of ˙M 0.1 M⊕/Gyr — our model yields a present-day planet mass of 0.02 M⊕ or less than about twice the mass of the Moon. Mass loss rates depend so strongly on planet mass that bodies can reside on close-in orbits for Gyrs with initial masses comparable to or less than that of Mercury, before entering a final short-lived phase of catastrophic mass loss (which KIC 12557548b has entered). Because this catastrophic stage lasts only up to a few percent of the planet’s life, we estimate that for every object like KIC 12557548b, there should be 10–100 close-in quiescent progenitors with sub-day periods whose hard-surface transits may be detectable by Kepler — if the progenitors are as large as their maximal, Mercury-like sizes (alternatively, the progenitors could be smaller and more numerous). According to our calculations, KIC 12557548b may have lost ∼70% of its formation mass; today we may be observing its naked iron core. Key words: hydrodynamics – planets and satellites: atmospheres – planets and satellites: composition – planets and satellites: physical evolution – planet-star interaction Monday, March 31, 2014
  • 79. for comparison. 2.4. Thermal structure The interior structures may fall into three categories, depending on the stellar distance, orbital history and atmospheric composition: migration of the melt towards the upper ocean. The amount of melt pro- duced by the internal heating in the kind of planet described in this Note is on the order of 1 km thick layer per Myr at the interface. This is quite small compared to the size of the ice layer. Consequently, the temperature profile in the ice mantle follows the solid/liquid transition curve, i.e., from 1150 K at the silicate interface to the temperature at the bottom of the ocean. Fig. 1. From left to right: (1) calculated internal structure of a 6M⊕ Ocean-Planet. Constituents are, from the centre to the outside, 1M⊕ metals, 2M⊕ silicates, and 3M⊕ ice. The density (g cm−3) at the centre, different interfaces and top is: 19.5, 15.6–8.2, 6.2–3.9, and 1.54; gravity (g⊕): 0, 2.1, 1.96, and 1.54; pressure (GPa): 1580, 735, 250, and ∼ 1. The upper layer is a ∼ 100 km thick ocean. The mean planetary density is 4.34 g cm−3; (2) idem for a rocky planet with the same total mass (2M⊕ metals, 4M⊕ silicates). Density is: 21.0, 15.5–8.1, and 4.1; gravity: 0, 2.72, and 2.24; pressure: 2200, 745, and 0. The mean planetary density is 7.74 g cm−3; (3) for comparison, the structure of the Earth calculated with the same model is shown. It agrees fairly well with the actual one. Density is: 13, 9.5–5.2, 3.3; gravity: 0, 1.04, 1.00; pressure: 340, 130, 0. The mean planetary density is 5.57 g cm−3. Monday, March 31, 2014
  • 80. Monday, March 31, 2014
  • 81. Monday, March 31, 2014

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