Detecting molecules in the atmospheres of transit Exoplanets Giovanna Tinetti University College London Mao-Chang Liang Academia Sinica, Taiwan

(Schneider) What’s the Nature of these planets? >280

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 K Hot Jupiter?

The chemistry of Hot-Jupiters C/O ratio = solar Photochemistry predicted with “ Kinetics ” (Liang et al., 2003,2004) Tinetti, Liang, et al., ApjL, 2007 CO & H 2 O

Following the planet during its orbit

Courtesy of S. Seager Transiting planets Transit [R p /R * ] 2 ~ –Transit radius Emission spectra T p /T * (R p /R * ) 2 ~10 -3 –Emitting atmosphere  ~2/3 –Temperature and  T Transmission spectra [atm/R * ] 2 ~10 -4 –Upper atmosphere –Exosphere ( ) Reflection spectra p[R p /a] 2 ~10 -5 –Albedo, phase curve –Scattering atmosphere Before direct imaging

Spectral signature of a transiting planet Star flux Wavelength

~ 1% Star flux Spectral signature of a transiting planet Wavelength ~ R p 2 /R s 2

~0,01% ~ 1% Wavelength Star flux Spectral signature of a transiting planet ~Rp 2 /Rs 2 ~Anulus 2 /Rs 2

4.5 hours on October 31, 2006 at 3.6 and 5.8 μm 33 hours on November 2, 8 μm SPITZER OBSERVATIONS

Star flux At 3.6, 5.8 and 8  m, the planet shows different transit depths: something is absorbing in its atmosphere! IRAC observations in the IR, primary transit for HD b ~ 0.08%

Tinetti et al., Nature, 448, 163, 2007 Water, T-P ~ bar, 700  bar Water line list: BT2 Barber et al., 2006

Tinetti et al., Nature, 448, 163, 2007 T = 500 K T = 2000 K

Na K H 2 -H 2 H2OH2O Tinetti et al., Nature, 448, 163, 2007 Knutson et al., 2007 Winn 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

Swain, Vasisht, Tinetti, Nature, 452, 2008 HST-NICMOS Primary transit

Swain, Vasisht, Tinetti, Nature, 452, 2008 HST-NICMOS Primary transit

Emission spectrum: the day side, water and CO Charbonneau et al., 2008; Barman, 2008 HD b: 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! Hot-Jupiters

Cavarroc, Cornia, Tinetti, Boccaletti, in preparation James Webb Space Telescope performances (MIRI) 10, 20, 30 parsec G star

Radial velocity / Occultation Period = days Period = days Mass = 0.69 ±0.05 M Jupiter Radius = 1.35 ±0.04 R Jupiter Density = 0.35 ±0.05 g/cm 3 Density = 0.35 ±0.05 g/cm 3 HD b

Primary Transit Star Flux Charbonneau et al., 2000

Secondary Transit Star+Planet Flux +

Beaulieu et al., ApJ, in press Knutson et al., Nature, 2007 Primary transit + IR + Spitzer

Emission spectra: thermal profiles Knutson et al., 2007; Burrows et al.,2007a,2007b HD b: water in emission HD b: water in absorption

Burrows et al.,ApJ, 2006 T(K) Log P (bar)