Transmission spectra of exoplanet atmospheres

Transcription

1 Transmission spectra of exoplanet atmospheres David Ehrenreich Grenoble Institute of Planetology and Astrophysics (IPAG) Alain Lecavelier des Etangs (IAP) David K. Sing (U Exeter) J.-M. Désert (Harvard)

2 Primary transit

3 Primary transit The planet (partially) eclipses the star Transmission spectroscopy through the limb

4 Chromatic variations of the optically-thick radius Normalised flux 883 nm 767 nm 758 nm 679 nm GranTeCan spectrophotometry hot jupiter XO-2b Sing et al. (2011) Phase F/F (λ) [R p (λ)/r ] 2 larger absorptions = larger radius/altitude Seager & Sasselov (2000) Brown (2001) Hubbard et al. (2001) Ehrenreich et al. (2006)

5 Chromatic variations of the optically-thick radius Planet radius (RJ) GranTeCan spectrophotometry hot jupiter XO-2b Sing et al. (2011) Fernandez et al. (2009) Fortney et al. (2010) Wavelength (Å) F/F (λ) [R p (λ)/r ] 2 larger absorptions = larger radius/altitude Seager & Sasselov (2000) Brown (2001) Hubbard et al. (2001) Ehrenreich et al. (2006)

6 Chromatic variations of the optically-thick radius (ΔF/F) atmo 2(ΔF/F) p (H/R p ) scale height H = k B T/µg Winn (2010)

7 Chromatic variations of the optically-thick radius (ΔF/F) atmo 2(ΔF/F) p (H/R p ) ~500 km scale height H = k B T/µg Winn (2010)

8 Chromatic variations of the optically-thick radius (ΔF/F) atmo 2(ΔF/F) p (H/R p ) ~500 km ~10 km scale height H = k B T/µg Winn (2010)

9 Brighter star, better atmospheric detection S/N F A background light source is required for transmission spectroscopy: the transited star

10 Space- & ground-based results, from UV to NIR In the visible from the ground with Subaru & GranTeCan High-resolution detection of atmospheric tracers (Na & K) In the visible/nir from space with the HST HD b: temperature inversion & diffusion HD b: diffusion by haze In the UV from space with the HST Atmospheric evaporation of hot jupiters In the NIR from space with Spitzer & HST/Nicmos Molecular composition of hot gas giants

11 Focus on a couple of studies In the visible from the ground with Subaru & GranTeCan High-resolution detection of atmospheric tracers (Na & K) In the visible/nir from space with the HST HD b: temperature inversion & diffusion HD b: diffusion by haze In the UV from space with the HST Atmospheric evaporation of hot jupiters In the NIR from space with Spitzer & HST/Nicmos Molecular composition of hot gas giants

12 Atmospheric properties of a hot jupiter Absorption depth (%) Altitude (km) Wavelength (Å) Charbonneau et al. (2002) Sing et al. (2008a,b) Snellen et al. (2008) Lecavelier et al. (2008) Désert et al. (2008)

13 Atmospheric properties of a hot jupiter HD b HST/STIS low res Absorption depth (%) Altitude (km) Wavelength (Å) Charbonneau et al. (2002) Sing et al. (2008a,b) Snellen et al. (2008) Lecavelier et al. (2008) Désert et al. (2008)

14 Atmospheric properties of a hot jupiter HD b HST/STIS low res Absorption depth (%) Rayleigh scattering by H2 broad Na plateau Altitude (km) Wavelength (Å) Charbonneau et al. (2002) Sing et al. (2008a,b) Snellen et al. (2008) Lecavelier et al. (2008) Désert et al. (2008)

15 Atmospheric properties of a hot jupiter HD b HST/STIS low res HST/STIS med res Absorption depth (%) Rayleigh scattering by H2 broad Na plateau Altitude (km) Wavelength (Å) Charbonneau et al. (2002) Sing et al. (2008a,b) Snellen et al. (2008) Lecavelier et al. (2008) Désert et al. (2008)

16 Atmospheric properties of a hot jupiter HD b HST/STIS low res narrow Na core HST/STIS med res Absorption depth (%) Rayleigh scattering by H2 broad Na plateau Altitude (km) Wavelength (Å) Charbonneau et al. (2002) Sing et al. (2008a,b) Snellen et al. (2008) Lecavelier et al. (2008) Désert et al. (2008)

17 Atmospheric properties of a hot jupiter HD b HST/STIS low res narrow Na core HST/STIS med res Absorption depth (%) Rayleigh scattering by H2 broad Na plateau Na depletion ionization? condensation? Altitude (km) Wavelength (Å) Charbonneau et al. (2002) Sing et al. (2008a,b) Snellen et al. (2008) Lecavelier et al. (2008) Désert et al. (2008)

18 Atmospheric properties of a hot jupiter HD b HST/STIS low res narrow Na core HST/STIS med res Absorption depth (%) Rayleigh scattering by H2 broad Na plateau Na depletion ionization? condensation? Altitude (km) model TiO/VO driving thermal inversion? Wavelength (Å) Charbonneau et al. (2002) Sing et al. (2008a,b) Snellen et al. (2008) Lecavelier et al. (2008) Désert et al. (2008)

19 Atmospheric properties of a hot jupiter HD b HST/STIS low res narrow Na core HST/STIS med res Absorption depth (%) Rayleigh scattering by H2 broad Na plateau Na depletion ionization? condensation? Altitude (km) model TiO/VO driving thermal inversion? Wavelength (Å) Charbonneau et al. (2002) Sing et al. (2008a,b) Snellen et al. (2008) Lecavelier et al. (2008) Désert et al. (2008)

20 Temperature inversion Absorption depth (%) Altitude (km) 2000 isotherms (K) Wavelength (Å) Sing et al. (2008a,b) Charbonneau et al. (2002) Snellen et al.(2008)

21 Temperature inversion Absorption depth (%) Altitude (km) 2000 isotherms (K) Wavelength (Å) Sing et al. (2008a,b) Charbonneau et al. (2002) Snellen et al.(2008)

22 Temperature inversion Absorption depth (%) Altitude (km) 2000 isotherms (K) Wavelength (Å) Sing et al. (2008a,b) Charbonneau et al. (2002) Snellen et al.(2008)

23 Connection to the upper atmosphere upper atmosphere T-P profile Yelle (2004) 10,000 K thermosphere EUV heating Pressure (bar) lower atmosphere T-P profiles Barman et al Showman et al Guillot 2010 Temperature (K) Vidal-Madjar et al. (2011)

24 Primary transit absorption ~1% ~0.01% The planet (partially) eclipses the star Transmission spectroscopy through the limb

25 Primary transit in the UV evaporating hydrogen upper atmosphere absorption ~1% ~10% Transits in HI Lyman-α (1216 Å) Exospheric studies (dynamics & composition)

26 Escape of light & heavy elements from HD209458b Flux (10-14 erg cm -2 s -1 Å -1 ) HST/STIS Wavelength (Å) Flux (10-15 erg cm -2 s -1 Å -1 ) HST/COS C II lines 7.8±1.3% HST/COS Si III 1206 Å 8.2±1.4% Velocity (km s -1 ) Velocity (km s -1 ) Vidal-Madjar et al. (2003, 2004) Linsky et al. (2010) see also: Ehrenreich et al. (2008) Fossati et al. (2010)

27 Escape of light & heavy elements from HD209458b Flux (10-14 erg cm -2 s -1 Å -1 ) HST/STIS Wavelength (Å) Hydrodynamical mass loss H flow carrying up heavier species Flux (10-15 erg cm -2 s -1 Å -1 ) HST/COS C II lines 7.8±1.3% HST/COS Si III 1206 Å 8.2±1.4% Velocity (km s -1 ) Velocity (km s -1 ) Vidal-Madjar et al. (2003, 2004) Linsky et al. (2010) see also: Ehrenreich et al. (2008) Fossati et al. (2010)

28 Another case of evaporating hot jupiter: HD b HST/ACS Lecavelier des Etangs et al. (2010)

29 Another case of evaporating hot jupiter: HD b HST/ACS Lecavelier des Etangs et al. (2010)

30 Another case of evaporating hot jupiter: HD b HST/ACS HI Lyα 5.1±0.8% transit in the visible is 2.4% Lecavelier des Etangs et al. (2010)

31 Another case of evaporating hot jupiter: HD b HST/ACS HI Lyα 5.1±0.8% transit in the visible is 2.4% mass-loss rate ~ g s -1 hot jupiters are stable lifetime estimations Lecavelier des Etangs et al. (2010)

32 Lifetime heating efficiency=15% Log [Gravitational potential energy (erg)] WASP-33b WASP-12b WASP-17b HD189733b HD209458b Corot-7b HD80606b GJ436b Kepler-9d Kepler-10b GJ1214b Log [Incident X/EUV energy on top of the atmosphere (erg Gyr -1 )] Ehrenreich & Désert (2011) also: Lecavelier (2007) Davies & Wheatley (2009) Lammer et al. (2009)

33 Lifetime heating efficiency=15% Log [Gravitational potential energy (erg)] WASP-33b WASP-12b WASP-17b HD189733b HD209458b Corot-7b HD80606b GJ436b Kepler-9d Kepler-10b GJ1214b Log [Incident X/EUV energy on top of the atmosphere (erg Gyr -1 )] Ehrenreich & Désert (2011) also: Lecavelier (2007) Davies & Wheatley (2009) Lammer et al. (2009)

34 Present-day transit surveys detect VIPs (mostly) at large distances Lifetime Log [Gravitational potential energy (erg)] too far to < 200 pc HD80606b Log [Incident X/EUV energy on top of the atmosphere (erg Gyr -1 )] Atmospheric tracer (HI) absorbed by ISM nearby targets necessary! PLATO will survey nearby M-dwarf stars

35 Why we need Plato 7 Known transiting planets 8 Known transiting planets 9 10 V (mag) ,00 0,01 0,02 0,03 0,04 0,05 Atmospheric signal of 1 scale height (%)

36 Why we need Plato 7 Known transiting planets 8 9 Known transiting planets 3σ detection of 1 scale height by HST 10 V (mag) ,00 0,01 0,02 0,03 0,04 0,05 Atmospheric signal of 1 scale height (%)

37 Why we need Plato 7 Known transiting planets 8 9 Known transiting planets 3σ detection of 1 scale height by HST 10 V (mag) σ detection of 1 scale height by JWST /HST ,00 0,01 0,02 0,03 0,04 0,05 Atmospheric signal of 1 scale height (%)

38 Why we need Plato Known transiting planets PLATO planets around bright stars Known transiting planets population synthesis model welcome to assess the characterization follow-up possibilities 3σ detection of 1 scale height by HST 10 V (mag) σ detection of 1 scale height by JWST /HST ,00 0,01 0,02 0,03 0,04 0,05 Atmospheric signal of 1 scale height (%)

39 Why we need Plato 7 Known transiting planets 8 Known transiting planets 9 10 V (mag) ,00 0,01 0,02 0,03 0,04 0,05 Atmospheric signal of 1 scale height (%)

40 Why we need Plato Known transiting planets 3,000+ stars Known transiting planets V (mag) ,000+ stars 245,000+ stars ,00 0,01 0,02 0,03 0,04 0,05 Atmospheric signal of 1 scale height (%)...and more

41 Thank you!