A search for starlight reflected from υ And’s innermost planet

In data from three clear nights of a WHT/UES run in 2000 Oct/Nov, and using improved Doppler tomographic signal-analysis techniques, we have carried out a deep search for starlight reflected from the innermost of υ (upsilon) And’s three planets. We place upper limits on the planet’s radius Rp as functions of its projected orbital velocity Kp ≈ 139 sin i km s for various assumptions about the wavelengthdependent geometric albedo spectrum p(λ) of its atmosphere. For a grey albedo p we find Rp √ p < 0.98 RJ with 0.1% false-alarm probability (4-σ). For a Sudarsky, Burrows & Pinto (1999) Class V model atmosphere, the mean albedo in our 380-676 nm bandpass is 〈p〉 ∼ 0.42, requiring Rp < 1.51 RJ , while an (isolated) Class IV model with 〈p〉 ∼ 0.19 requires Rp < 2.23 RJ . The star’s vrot sin i ∼ 10 km s and estimated rotation period Prot ∼ 10d suggest a high orbital inclination i ∼ 70 − 80◦. We also develop methods for assessing the false-alarm probabilities of faint candidate detections, and for extracting information about the albedo spectrum and other planetary parameters from faint reflected-light signals.