160 likes | 269 Views
Ground-based Exoplanet Atmospheres Characterization: Progress Since the 2009 Breakthrough. Mercedes L ópez-Morales Carnegie Institution of Washington. Hubble Fellows Symposium 2010.
E N D
Ground-based Exoplanet Atmospheres Characterization: Progress Since the 2009 Breakthrough Mercedes López-Morales Carnegie Institution of Washington Hubble Fellows Symposium 2010 Collaborators: Daniel Apai (STScI), David Sing (Exeter, UK), Sara Seager (MIT), Justin Rogers (JHU/CIW), Adam Burrows (Princeton), Jeff Coughlin (NMSU), Michael Sterzik (ESO)
Nov 1995: discovery of 51 Pegasi bby Mayor & Queloz; confirmed by Marcy & Butler on December 1995. March 2010: more than 400discovered. Finding Earth-mass planets Atmospheric characterization Star’s Spectral Type: G2V Mp sin i = 0.468 Mjup; P = 4.23077 day
How can we measure an exoplanet’s atmosphere? • Direct Imaging Secondary Eclipse • Transits Secondary eclipse (< 0.1 - 0.2% of total light) Primary Eclipse Primary eclipse (~ 1% of total light) Real data for HD 189733b (Knutson et al. 2007)
Primary Eclipses: Transmission Spectra (Tinetti et al. 2007) Exoplanet atmosphere’s spectrum Secondary Eclipses: Emission spectra ; Showman & Guillot 2002 López-Morales & Seager 2007
First exoplanet atmosphere detections Sodium (HD 209458b) Secondary @ 24 μm (HD 209458b) (Charbonneau et al. 2002) (Deming et al. 2005) HST/STIS Spitzer/MIPS
Results from the ground 8.0-m VLT 4.2-m WHT 3.5-m APO + HET, Subaru, IRTF 6.5-m Magellan
Primary Eclipses: Transmission Spectra Ground-based detection of Sodium in HD 189733b (Redfield et al. 2008) > 3 detection Ground-based confirmation of Sodium in HD 209458b (Snellen et al. 2008) = 3.0 Å Depth = 0.056% = 0.75 Å Depth = 0.135% > 5 detection
Secondary Eclipse: Thermal + Reflected Emission Ogle-TR-56b TrES-3b (Sing & López-Morales 2009) (de Mooij & Snellen 2009) 8-m VLT + 6.5-m Magellan z’-band (0.9 m) Depth = 0.036% (3.6) 4.5-m WHT K-band (2.2 m) Depth = 0.241% (~6) TK = 2040 ± 185 K AB ~ 0.0 (no-clouds) f ~ 2/3 (low winds) Tz’ = 2718 ± 120 K AB ~ 0.0 (no-clouds) f ~ 0.56 (low winds) Thermal Inversion Thermal Inversion
Secondary Eclipse: Thermal + Reflected Emission CoRoT-1b (Gillon et al. 2009) (Rogers et al. 2009) 8-m VLT 3.5-m APO HJD (days) NB2090 (2.09 m) Depth = 0.278% (~5) Ks-band (2.2 m) Depth = 0.324% (7.7) Tz’ = 2460 (+80/-160) K AB ~ 0.00 (+0.08/-0.00) f ~ 0.52 (+0.07/-0.08) Flux Fν [ Jy ] Heat Redistribution Factor (f) Prominent dT between day and night sides Bond Albedo AB (Rogers et al. 2009) Bond Albedo AB
Secondary Eclipse: Thermal + Reflected Emission • - Models for different f (Pn) and • extra-absorber opacities κe • The extra-absorber is at • Pheight = 1 mbar • - Models reproduce emission in the optical, but near-IR emission is twice larger than predicted. - Attempt to reproduce the near- IR emission using Pn = 0.1 and extra-absorber with κe = 0.05 cm2g-1 at Pheight = 10 mbar - Models still cannot reproduce near-IR emission. (Rogers et al. 2009) ** Atmospheric models generated by co-author A. Burrows
Secondary Eclipse: Thermal + Reflected Emission WASP-12b (López-Morales et al. 2010) 3.5-m APO z’-band (0.9 m) Depth = 0.082% (5.4) Eclipse’s central phase = 0.5100 ± 0.0022 e |cosω| = 0.0156 ± 0.0035 e = 0.057 ± 0.013 (assuming ω = 74°) • The measured z’-band depth fits well BB models and atmospheric models with and w/o thermal inversions. Need more λ’s. (Hebb et al. 2009)
Secondary Eclipse: Thermal + Reflected Emission WASP-19b (Anderson et al. 2010) (Gibson et al. 2010) 8-m VLT 8-m VLT H-band (1.62 m) Depth = 0.259% (~5.7) NB2090 (2.09 m) Depth = 0.366% (~5) • The hottest possible models cannot reproduce the H-band depth. • The 2.09 m atmosphere is slightly better reproduced, but still ~ 1-sigma brighter than the models.
Secondary Eclipse: Spectro-photometry HD 189733b (Swain et al. 2010) • Day-side observations between 2.0 – 2.4 μm and 3.0 – 4.1 μm • Spectro-photometry with R= 470 Depth > 1.0%(>10) Eclipse depths agree when compared to available HST and Spitzer data.
Secondary Eclipse: Spectrophotometry HD 189733b (Swain et al. 2010) Non-LTE? LTE models OK
Conclusions • We have now observed the atmospheres of 7 Hot Jupiters from the ground: • transmission NaI D signals of 2 planets in 2008 • emission photometry of 5 planets in 2009-2010 • spectro-photometry of 1 exoplanet in 2010 • For CoRoT-1b we can now assure that AB ~ 0 and the planet • does have a much hotter day-side than night-side (thermal • inversion layer) • hints of the same behavior in other planets, but need • more color measurements • Previously untested models seem to have problems reproducing the emission of some hot Jupiters in the near-IR. Non-LTE?? • Observational improvements in the next few years will be aimed at studying the atmospheres of the first transiting exo-Earths