detecting molecules in the atmospheres of transit exoplanets giovanna tinetti university college...
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Detecting molecules in the atmospheres of transit Exoplanets
Giovanna TinettiGiovanna Tinetti
University College LondonUniversity College London
Mao-Chang LiangMao-Chang Liang
Academia Sinica, TaiwanAcademia Sinica, Taiwan
Hot-Jupiters are Gas-Giant planets, orbiting VERY close to
their parent star.
They are probably tidally locked, i.e. one face is always
illuminated and the other is in perpetual darkness.
They easily reach Temperatures 1000-2000 K
Hot Jupiter?Hot Jupiter?
The chemistry of Hot-Jupiters The chemistry of Hot-Jupiters C/O ratio = solar C/O ratio = solar
Photochemistry Photochemistry predicted with “predicted with “KineticsKinetics” ” (Liang et al., 2003,2004)(Liang et al., 2003,2004)
Tinetti, Liang, et al., ApjL, 2007
CO & H2O
Courtesy of S. Seager
Transiting planets
• Transit [Rp/R*]2 ~ 10-2
– Transit radius
• Emission spectra Tp/T*(Rp/R*)2 ~10-3
– Emitting atmosphere ~2/3– Temperature and T
• Transmission spectra [atm/R*]2 ~10-4
– Upper atmosphere– Exosphere (0.05-0.15)
• Reflection spectra p[Rp/a]2~10-5
– Albedo, phase curve– Scattering atmosphere
Before direct imaging
Spectral signature of a Spectral signature of a transiting planettransiting planet
Star flux
Wavelength
~ 1%
Star flux
Spectral signature of a Spectral signature of a transiting planettransiting planet
Wavelength
~ Rp2/Rs
2
~0,01%
~ 1%
Wavelength
Star flux
Spectral signature of a Spectral signature of a transiting planettransiting planet
~Rp2/Rs2
~Anulus2/Rs2
5.8 8 3.6
Star fluxAt 3.6, 5.8 and 8 m,
the planet shows different transit depths:
something is absorbingin its atmosphere!
IRAC observations in the IR,IRAC observations in the IR,primary transit for HD 189733bprimary transit for HD 189733b
~ 0.08%
Tinetti et al., Nature, 448, 163, 2007
Water, T-P ~ 1200 K @ 1 bar, 700 K @ bar
Water line list: BT2
Barber et al., 2006
Na
K
H2-H2
H2O
Tinetti et al., Nature, 448, 163, 2007
Knutson et al., 2007Winn et al., 2007
Beaulieu et al., 2007
Star spots/hazes?
There is something more….
Beaulieu et al., 2007
Knutson et al., 2007
Swain et al., 2007
Pont et al., 2007
Emission spectrum: the day side,Emission spectrum: the day side,water and COwater and CO
Charbonneau et al., 2008; Barman, 2008
HD 189733b: water in absorption
Hot-Jupiters have become a very hot subject, theory and observations are
boosting each-others For thermal structure and chemistry we
have already made the leap to 3D There is a variety of hot-Jupiters, not
only one prototype Primary & secondary transits,
widest possible spectral coverage, spectroscopy and photometry, space & ground based telescopes:
We want them all!
HotHot-Jupite-Jupitersrs
Cavarroc, Cornia, Tinetti, Boccaletti, in preparation
James Webb Space Telescope James Webb Space Telescope performances (MIRI)performances (MIRI)
Planet @ 10, 20, 30 parsec G starG star
Radial velocity / OccultationRadial velocity / Occultation
Period = 3.524738 daysPeriod = 3.524738 days
Mass = 0.69 ±0.05 MMass = 0.69 ±0.05 MJupiterJupiter
Radius = 1.35 ±0.04 RRadius = 1.35 ±0.04 RJupiter Jupiter
DensityDensity = 0.35 ±0.05 g/cm= 0.35 ±0.05 g/cm33
HD 209458bHD 209458b
Beaulieu et al., ApJ, in press
Knutson et al., Nature, 2007
Primary transit + IR + SpitzerPrimary transit + IR + Spitzer
Emission spectra: thermal profilesEmission spectra: thermal profiles
Knutson et al., 2007; Burrows et al.,2007a,2007b
HD 209458b: water in emission HD 189733b: water in absorption