Astrophysics, abstract
astro-ph/0612172

From: Daniel Grether [view email]

Date: Thu, 7 Dec 2006 03:49:42 GMT (178kb)

The Metallicity of Stars with Close Companions

Authors: Daniel Grether (School of Physics, University of New South Wales), Charles H. Lineweaver (Planetary Science Institute, Research School of Astronomy and Astrophysics & Research School of Earth Sciences, Australian National University)

Comments: 40 pages, 17 figures

We examine the relationship between the frequency of close companions (stellar and planetary companions with orbital periods < 5 years) and the metallicity of their Sun-like (~ FGK) hosts. We confirm and quantify a ~4 sigma positive correlation between host metallicity and planetary companions. We find little or no host-mass-dependence or distance-dependence in this correlation. In contrast to the metallicity dependence of planetary companions, stellar companions tend to be more abundant around low metallicity hosts. At the ~2 sigma level we find an anti-correlation between host metallicity and the presence of a stellar companion. Upon dividing our sample into FG and K sub-samples, we find a negligible anti-correlation in the FG sub-sample and a 3 sigma anti-correlation in the K sub-sample. A kinematic analysis suggests that this anti-correlation is produced by a combination of low-metallicity, high-binarity thick disk stars and higher-metallicity, lower-binarity thin disk stars.

http://arxiv.org/abs/astro-ph/0612172