A Search for the Spectroscopic Signature of Hot Jupiters

We describe a method by which hot extrasolar planets close to their parent star may be directly detected through the signature of water vapour or methane in their infrared spectra, lying on top of the spectrum of the parent star. Upper limits derived from low resolution K band spectra of several ‘hot Jupiter’ systems are presented. We find no water vapour to 3-σ limits of between 1 part in 200 and 1 part in 600 for each star. Comparison with an initial model indicates that constraints can be set on the size, albedo, temperature and dust content of the planets.