Adam Burrows, Princeton April 7, KITP Public Lecture

Transcription

1 Adam Burrows, Princeton April 7, 2010 KITP Public Lecture

2 The Ancient History of Comparative Planetology There are infinite worlds both like and unlike this world of ours...we must believe that in all worlds there are living creatures and plants and other things we see in this world --- Epicurus (c. 300 BCE) (died painfully 269 BCE) false and damnable... G. Galilei (b. 1564) (life imprisonment 1633) M. Devirian IEEEAC#1124 2

3 Milestones >500 Exoplanets detected, mostly Giant Planets (e.g. Jupiters) ~ 70 transiting planets, Detection of H 2 O, CO, Na, maybe CO 2, CH 4 Spitzer and NICMOS light curves and secondary eclipse measurements Many temperatures measured GJ 436b and HAT-P-11b: Neptunes in Transit! >70 Neptunes and Super-Earths HD b with a ~80 Earth-mass core HD with high e: light curve and secondary transit! ~3.3 Earth-mass object orbiting a brown dwarf; 3 Pulsar planets (Wolszczan and Frail 1992) Several > Earth-mass planets by RV and transit techniques (e.g., CoRoT-7bc, GL 581e, GJ 1214b) **Discoveries of Fomalhaut b and HR 8799bcd, and perhaps β Pic b 3

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5 Stars and Planets Giant Giant Planet Planets Formation 5 5

6 Giant and Terrestrial Planets Giant Planet Formation Giant Planets 6 6

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9 Radial Velocity Technique Doppler Shift (Radar gun) Can ~measure planet mass 9

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12 51 Peg b 0.05 AU!! times closer than Jupiter-Sun Distance 12

13 Astrometry (Wobble Motion) Technique See-Saw 13

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16 SIM: 16

17 Microlensing Technique Einsteinian Bending of Light (Light Amplification) 17

18 Microlensing: 17 Planets found so far! 18

19 Transit Technique Primary Eclipse - Partial Eclipse of Star (can measure Radius) 19

20 Transiting Planets Secondary Eclipse See thermal radiation and reflected light from planet disappear and reappear Transit See stellar flux decrease (function of wavelength) Orbital Phase Variations See cyclical variations in brightness of planet figure taken from H. Knutson 20

21 Venus Transit of 1882: 21

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24 Transit by HD209458b (with HST/STIS) Can measure planet radius! R p ~ 1.32 R J ~1.5% dip: Charbonneau, Brown et al. 2001, 2002,

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26 High-Z Planet (T. Guillot) 26

27 70 Planets Are Known to be Transiting. Some planets appear to be inflated Massive planets on highly eccentric orbits Ice/Rock Planets 27

28 Na-D HD209458b: Radius is Larger in Na-D! Na detection: Charbonneau et al

29 Transit Radius vs. Wavelength aka. transmission spectroscopy? Fortney et al

30 Statistics/Facts of Exoplanets 30

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33 Ups And System 33

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35 Ongoing Surveys Have Discovered 500+ Planets So Far RV Planets Transiting Planets 35

36 HD 80606b Heats Up During Periastron Passage Spitzer will obtain phase curves for several Laughlin more et eccentric al. (2009), planets 8 μm (HAT-P-2, HD 17156, XO-3) during the warm mission. 36

37 HD 80606b Heats Up During Periastron Passage Laughlin et al. (2009), 8 μm Spitzer will obtain phase curves for several more eccentric planets (HAT-P-2, HD 17156, XO-3) during the warm mission. 37

38 51 Peg b HARPS 38

39 Mayor et al. A&A 2009 An emerging population of Hot Neptunes and Super-Earths P 1 = 4.31 days e 1 = 0.02 m 1 sini = 4.3 M P 2 = 9.62 days e 2 = 0.03 m 2 sini = 6.9 M P 3 = 20.5 days e 3 = 0.04 m 3 sini = 9.7 M HD K2 V Dist 12.8 pc [Fe/H] = O-C = 0.85 m/s 135 observations + drift = 0.5 m/s/y 39

40 Two super-earth (5-7 MEarth) in a 4-planet system + a very light planet of 1.94 MEarth Gl 581, M3V star Mayor et al Bonfils et al P1=3.15 d M1=1.94MEarth P2=5.37d M2=15.7MEarth P3=12.9 d M3=5.4MEarth P4= 66.8 d M4= 7.1 MEarth Udry et al Udry et al revised in Mayor et al

41 transit RV microlensing 41

42 Some properties of close-in low-mass planets 1) Mass distribution Observations (normalized distribution) Models (Mordasini et al. 2009) super-earths Prediction of a large population of terrestrial planets Giant planets 42

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44 Transits from space Radial Velocity From the ground Microlensing Space Astrometry? 44

45 Beyond Hot Jupiters: The Age of Kepler Kepler will find many new systems, perhaps Earths 45

46 COROT COROT-7b 1.7 REarth Transits of terrestrial planets Giant planets : 0.01 mag Terrestrial planets: mag Transits from space Kepler: waiting for results CoRoT: CoRoT-7b KEPLER 46

47 Planet diversity CoRoT, M-Dwarf surveys Transiting planets Transit fractional radius (relative to host star) inclination. RV planetary mass 2 solid planets: - CoRoT-7b : Period ~ 0.85 d - MEarth-1b: Period ~ 1.50 d Radius (Earth Units) => Diversity 47

48 Transit Technique Secondary Eclipse (eclipse of planet by star) 48

49 Transiting Planets Secondary Eclipse See thermal radiation and reflected light from planet disappear and reappear Transit See stellar flux decrease (function of wavelength) Orbital Phase Variations See cyclical variations in brightness of planet figure taken from H. Knutson 49

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51 Spitzer ST: 51

52 ? Water CH 4? CO JWST!! 52

53 Water in Emission!! H 2 O IRAC 1 < IRAC 2! Burrows et al

54 Burrows et al

55 Temperature Inversion! IRAC 1 < IRAC 2! Burrows et al

56 Direct Detection and Imaging of planetary systems 56

57 Jupiter s Spectrum (T. Guillot) 57

58 Planet/Star Flux ratio versus Orbital Distance CIA Burrows, Sudarsky, and Hubeny

59 N.B.,Jupiter at 2 AU does not have NH 3 clouds, but does have H 2 O clouds Clouds Burrows et al

60 Fomalhaut b a ~ 115 AU!! Kalas et al. 2008; < 3 M J 60

61 HR 8799bcd M b ~ 7 M J M c ~10 M J M d ~10 M J D = 24, 38, 68 AU Marois et al

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63 Planet/Star Contrast: Theory (dashed) versus Capability HR 8799!! (Burrows 2005) Red: H band (1.6 microns); Purple: Mid-IR; Green: Optical 63

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68 Planetary (Phase) Light Curves 68

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70 Phase Functions: Burrows et al

71 Mapping the Day-Night Circulation With Phase Curves Size of observed variation depends on efficiency of day/night circulation Efficient Inefficient Image courtesy G. Laughlin 71

72 First Longitudinal Temperature Profile for an Exoplanet: HD b s Warm Night Side 1200 K 1000 K 1000 K 1200 K (Knutson slide) Spitzer 8 μm observations of HD b (Knutson et al. 2007b, Nature 447, 183). 72

73 ~Same behavior at 24 µm! Hot spot and cold spot on same hemisphere! Transiting 73

74 Planet/Star Flux Ratio vs. Wavelength and Phase Burrows, Rauscher, Spiegel, & Menou

75 J band HD b Map (model a00) 75

76 IRAC3 band HD b Map (model a03) 76

77 I band HD b Map (model a03) 77

78 Methane Map: w/o U/A heating 78

79 Methane Map: with U/A heating 79

80 The Future? 80

81 Schedule? COROT Kepler JWST Gaia SIM? TPF/Darwin precursor? Very large telescopes (LBT,GMT,TMT,ELT) TPF/Darwin? Very large space arrays 81

82 JWST 82

83 Any questions? Giant Planet Formation 83

84 Graphic by D. Spiegel 84

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