Bayesian Stellar Parameters and Evolutionary Stages for 372 Giants from the Lick Planet Search

For the understanding of exoplanets it is vital to determine accurate and precise stellar parameters of their host stars. We derived stellar parameters for 372 giants from the Lick planet search (Frink et al., 2001) by comparing spectroscopic, astrometric and photometric observables to grids of evolutionary models using Bayesian inference (Stock et al., to be submitted). In particular our method is able to provide probabilities for the current post-main sequence evolutionary stage (horizontal branch vs. red-giant branch). We find very good agreement between our stellar parameters and literature values. Some studies have questioned the reliability of stellar masses determined from evolutionary models, e.g., Schlaufman & Winn (2013). We used a sample of 26 giants with asteroseismic masses MA and Bayesian masses based on evolutionary tracks  ME and find no evidence for large systematic differences (〈ME−MA〉=0.04±0.22 M). We tested the reliability of our methodology to predict the evolutionary stage by using 1012 giants in the Kepler field with asteroseismically determined evolutionary stages and find an agreement for 86% of the stars. We find that 15 of the 16 (94%)  planet host stars of the Lick sample are more likely horizontal branch stars, while the fraction of horizontal branch stars in the full sample is 81%.

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