Primary transit observations of the hot Jupiter HD189733b

Jean-Philippe Beaulieu (IAP)Giovanna Tinetti (UCL)Sean Carey (SSC, IPAC)Ignasi Ribas (CSIC-IEEC) Mao-Chang Liang, Yuk Yung (CALTECH)Robert Barber, Jonathan Tennyson (UCL)Nicole Alard, David Sing (IAP)Franck Selsis (ENS Lyon)

Primary transit photometry Primary transit photometry

Brillance

Charbonneau et al., 2002; Vidal-Madjar et al., 2003, 2004;Richardson et al., 2006; Ballester, Sing, Herbert, 2007;Knutson et al., 2006, 2007; Beaulieu et al., 2007

Brillance 1

23

Charbonneau et al., 2002; Vidal-Madjar et al., 2003, 2004;Richardson et al., 2006; Ballester, Sing, Herbert, 2007;Knutson et al., 2006, 2007; Beaulieu et al., 2007

Primary transit photometry Primary transit photometry

Transmission spectroscopy and emission spectroscopy (primary-secondary transits) are two complementary techniques to probe exoplanetary atmospheres

Primary transits -> molecular abundances, clouds

Secondary transits -> T-P profiles, clouds

Ideally you want to use both!!!

To have a better understanding of the atmospheric processes, we need a broad wavelength range

Hot-Jupiters in transit

Photochemistry prediction

(Liang et al., 2003,2004)

Tinetti, Liang, et al., ApjL, 2007

CO & H2O

Water and CO in extrasolar planets

C/O < solar

C/O = solar

C/O > solar

Tinetti, et al., ApjL, 2007

Predicted transmission spectra of HD189733

Predicted difference 3.6-5.8 μm = 0.05 %

SPITZER OBSERVATIONS

4.5 hours on October 31, 2006 at 3.6 and 5.8 μm33 hours on November 2, 8 μm (Knutson et al., 2007, Nature)

SPITZER 5.8 μm, (channel 3)

SPITZER 3.6 μm, (channel 1)

We must beat down systematics !

Correcting for pixel phase effects

Morales-Calderon et al., 2006, IRAC handbook

Flux Correction= f(distance to pixel-center)

Estimating systematic trends from the data

MODELING THE LIGHT CURVE &

LIMB DARKENING

3.6 μm, LD-uniform = 0.027 %

5.8 μm, LD-uniform = 0.021 %

3.6 - 5.8 μm = 0.080 % (Uniform)3.6 - 5.8 μm = 0.074 % (LD)

HD189733, a spotted star

Winn et al., 2007, opticalPont et al., 2007, HST, 0.8 μm

Being a K star T~5000 K, it is not a surprise

An extreme spotted star model (Ribas)

Star a K star 20 % of the star covered with 1000 K cooler spots

In this extreme case : •Transit depth smaller by 0.58 % in the visible• Transit depth smaller by 0.19 % at 3.6 μm• Transit depth smaller by 0.18 % at 5.8 μm

Differential effect 3.6 – 5.8 μm = 0.01 %Differential effect visible - 3.6 μm = 0.39 %

Spots contribution is critical for optical – IR comparisonSpots contribution is critical for optical – IR comparisonDifferential effects at 3.6 – 5.8 Differential effects at 3.6 – 5.8 μμm are smallm are small

Measured transit depths at 3.6, 5.8, 8 μm

Knutson et al. 2007 measurement at 8 μm (uniform source) = 2.38 ± 0.02 %

Trasmission spectrum from the VIS to the far-IR

Na

K

H2-H2

H2O

Tinetti et al., Nature 448, 163

Abs. coeff.:(Allard N.,2006; Barber2006;Borisow et al., )

T-P profileIro et al., 2005Burrows et al., 2006

Richardson et al., 2006

Charbonneau et al., 2002Knuthson et al., 2007a

Knutson et al., 2007

Winn et al., 2007

Beaulieu et al. 2007

First detection of water vapor

Isotherme à 500 K

Isotherme à 2000 K

TP profils TP with terminator (Burrows et al. 2006)

Tinetti et al., Nature 448, 163

CONCLUSION• Water vapor has been detected by primary transit observation (3.6, 5.8

and 8 μm)

• In agreement with predictions and photochemistry models

• Possible to do high precision photometry with SPITZER

• HD209458, 20 hours of Spitzer observations scheduled in December (WETWORLD, Tinetti et al.)

Tinetti et al., Nature 448, 163Beaulieu et al., ApJ submitted

Predicted T-P profiles Predicted T-P profiles for day/night sidesfor day/night sides

Burrows et al., 2006

T (K)

T (K)P (b

ar)

P (b

ar)

Secondary transit: Secondary transit: simulated emission spectrasimulated emission spectra

Simulated emission spectrum,No clouds

Isothermal profile @ ~ 1800 K

Clouds @ 10-2-10-3 bars

Tinetti et al., Nature, 2007