Open AccessA search for the infrared spectroscopic signature of hot Jupiter planets
Author(s) -
Lucas P. W.,
Roche P. F.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05786.x
Subject(s) - physics , hot jupiter , planet , astrophysics , infrared , jupiter (rocket family) , astronomy , planetary system , atmosphere (unit) , exoplanet , spectral resolution , spectral line , space exploration , thermodynamics
We present the results of an attempt to detect the hottest ‘hot Jupiter’ planets directly in the thermal infrared. A simple method based upon high signal‐to‐noise ratio spectroscopy of the central star at low spectral resolution is described. In the 2–4 μm region the contrast ratio between planet and star is expected to be relatively low and the planetary spectrum should appear as a faint signal on top of the stellar spectrum, distinguished by edges of H 2 O absorption. No water edges were found to 3σ limits of one part in a few hundred in each case. These upper limits are compared with the irradiated planetary atmosphere models of Barman, Hauschildt & Allard to derive upper limits on the size of the hot Jupiters, which are expected to be somewhat larger than Jupiter. If reasonably strong H 2 O absorption occurs in these objects then typical upper limits of R < 3 R Jup are derived, the precision being limited by the stability of telluric transmission. Only a modest improvement in precision is needed (e.g. with space‐based instruments) to reach the range of greatest interest (1 < R < 2 R Jup ) .