Ground-based detection of the near-infrared emission from the dayside of WASP-5b

Abstract

(Abridged) WASP-5b is a highly irradiated dense hot Jupiter orbiting a G4V star every 1.6 days. We observed two secondary eclipses of WASP-5b in the J, H and K bands simultaneously. Thermal emission of WASP-5b is detected in the J and K bands. The retrieved planet-to-star flux ratios in the J and K bands are 0.168 +0.050/-0.052% and 0.269+/-0.062%, corresponding to brightness temperatures of 2996 +212/-261K and 2890 +246/-269K, respectively. No thermal emission is detected in the H band, with a 3-sigma upper limit of 0.166%, corresponding to a maximum temperature of 2779K. On the whole, our J, H, K results can be explained by a roughly isothermal temperature profile of ~2700K in the deep layers of the planetary dayside atmosphere that are probed at these wavelengths. Together with Spitzer observations, which probe higher layers that are found to be at ~1900K, a temperature inversion is ruled out in the range of pressures probed by the combined data set. While an oxygen-rich model is unable to explain all the data, a carbon-rich model provides a reasonable fit but violates energy balance.

13 pages, 9 figures, accepted for publication in A&A

References in corpus (12)

• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• Detection of Thermal Emission from an Extrasolar Planet
• The effect of red noise on planetary transit detection
• On the radiative equilibrium of irradiated planetary atmospheres
• GROND - a 7-channel imager
• Homogeneous studies of transiting extrasolar planets. I. Light curve analyses
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• Theoretical Spectra and Light Curves of Close-in Extrasolar Giant Planets and Comparison with Data
• Improved parameters for the transiting hot Jupiters WASP-4b and WASP-5b
• On the Absorption and Redistribution of Energy in Irradiated Planets
• WASP-5b: a dense, very-hot Jupiter transiting a 12th-mag Southern-hemisphere star
• Ground-based K-band detection of thermal emission from the exoplanet TrES-3b

Cited by in corpus (4)

• Ks band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope
• Observed spectral energy distribution of the thermal emission from the dayside of WASP-46b
• Colour-colour and colour-magnitude diagrams for Hot Jupiters
• Near infrared and optical emission of WASP-5 b