HD 75289Ab revisited

Searching for starlight reflected from a hot Jupiter

¹ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany e-mail: rodler@mpia.de
² Institut für Astronomie, Universität Wien, Türkenschanzstrasse 17, 1180 Vienna, Austria

Received: 30 November 2007
Accepted: 29 February 2008

Abstract

Aims. We attempt to detect starlight reflected from a hot Jupiter, orbiting the main-sequence star HD 75289Ab. We report a revised analysis of observations of this planetary system presented previously by another research group.

Methods. We analyze high-precision, high-resolution spectra, collected over four nights using UVES at the VLT/UT2, by way of data synthesis. We try to interpret our data using different atmospheric models for hot Jupiters.

Results. We do not find any evidence for reflected light, and, therefore, establish revised upper limits to the planet-to-star flux ratio at the 99.9% significance level. At high orbital inclinations, where the best sensitivity is attained, we can limit the relative reflected radiation to be less than assuming a grey albedo, and assuming an Class IV function, respectively. This implies a geometric albedo smaller than and , for the grey albedo and the Class IV albedo shape, respectively, assuming a planetary radius of .