Observations of Gas-Giant Exoplanet Atmospheres

Transcription

1 Observations of Gas-Giant Exoplanet Atmospheres Brian Jackson - NASA/GSFC

2 Earliest Observations of a Jovian atmosphere From Rogers (1995) The Giant Planet Jupiter.

3 Earliest Observationss of Jupiter's Weather Campani affirms he hath observed by the goodness of his glasses certain protuberancies and inequalities, much greater than those that have been seen therein hitherto. He addeth, that he is now observing whether those sallies in the said planet do not change their scituation. The ingenious Mr. Hook did, some moneths since, intimate to a friend of his that he had observed some days before he then spoke of it a small spot in [one of the] belts From Rogers (1995) The Giant Planet Jupiter.

4 Atmosphere Deming & Seager review in Nature 462, 301 (2009) Also, Seager & Deming ARAAA (2010), astro-ph/

5 Exploit transits to characterize exoplanet atmospheres Transits require photometric stability ~ 1 to 3 hours But tolerate poor image quality

6 First Light Thermal Emission Spitzer enables direct detection of IR light from the planets eclipse depth ~ (R p /R star ) 2 (T p /T star ) Six Spitzer photometric bands can give a low resolution spectrum of the planet

7 First Light Thermal Emission Charbonneau found himself locked in a race with Deming to be the Spitzer first enables to detect direct the secondary eclipse. detection of IR light from Deming the planets was observing HD b, with the Spitzer Space Telescope. Charbonneau, he knew, had collected eclipse depth ~ data on [TrES-1] a month earlier. We didn't want to be second, (R p /R star Deming ) 2 (T p /T star recalls. ) I was analyzing data while I was eating Christmas dinner. I had to catch Dave. yields T ~ 1100K In the end they published papers simultaneously and held a joint Six press Spitzer conference. photometric bands can give a low -- resolution spectrum of the planet

8 Knutson et al. (2007) HD b 33 hrs of Spitzer time

9 Cooper & Showman (2005)

10 Fortney et al. (2003)

11 Less offset Fortney et al. (2003) More offset

12 Knutson et al. (2007) HD b 33 hrs of Spitzer time

13 Knutson et al. (2008)

14 Inversions! Fortney et al. (2003)

15 Madhusudhan & Seager (2010)

16 HD b Emission! Knutson et al. (2008)

17

18 Inversion No Inversion

19 Knutson et al. (2010)

20 Croll et al. (2010) Secondary transit of WASP-12 b Ground-based observations at Ks (2.15um), H (1.6um), & J (1.25um)-bands

21 Li et al. (2010)

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24 HD bfor evaluation only.

25 Vidal-Madjar et al. (2004)

26 Linsky et al. (2010)

27 Borucki et al. (2009)

28 HAT-P-7 Welsh et al. (2010)

29 ~ 30% of FGKM stars host superearths, based on: Microlensing (Gould et al. 2006, ApJ 644, 237) Mayor et al. 2009, ApJ 493, 639) Radial Velocity Surveys (M Their atmospheres initially contain: H 2, H 2 O, CO, CO 2 Elkins-Tanton & Seager 2008 ApJ 685, 1237 Schaefer & Fegley 2009, astro-ph/ Miller-Ricci et al. 2009, ApJ 690, 1056 Outgassing from accretion and ongoing tectonics Both thermal and non-thermal atmospheric escape rates are uncertain so we here adopt the intermediate H 2 case of Miller-Ricci et al.

30 The James Webb Space Telescope 6.5 m diameter 26 m2 collecting area microns S. Seager

31 Example of carbon dioxide in a habitable SuperEarth

32 Mensus eram coelos, nunc terrae metior umbras Mens coelestis erat, corporis umbra iacet. I measured the skies, now the shadows I measure. Skybound was the mind, earthbound the body rests. Johannes Kepler