The metallicity dependence of giant planet incidence

Abstract

We describe three corrections that should be applied to the observed relative incidence of nearby stars hosting giant planets. These are diffusion in the stellar atmosphere, use of the [Ref] index in place of [Fe/H] for metallicity, and correction for local sampling with the W-velocity. We have applied these corrections to a subset of the SPOCS exoplanet survey with uniform giant planet detectability. Fitting the binned data to a power law of the form, α10β[Fe/H], we derived α = 0.022 ± 0.007 and β = 3.0 ± 0.5; this value of β is 50 per cent larger than the value determined by Fischer & Valenti. While the statistical significance of this difference is marginal, given the small number statistics, these corrections should be included in future analyses that include larger samples. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.