Abundances in the Local Region II: F, G and K Dwarfs and Subgiants

TL;DR

This study analyzes elemental abundances in 867 F, G, and K dwarf and subgiant stars, revealing modest enhancements over solar levels and examining implications for stellar and solar metallicity comparisons.

Contribution

It provides a comprehensive abundance analysis of 28 elements in a large sample of stars, including planet-hosts, and discusses the implications for solar and stellar metallicity.

Findings

Stars show a modest 0.05 dex enhancement in alpha, iron-peak, and transition metals.

Lanthanides are more abundant, averaging +0.2 dex over solar.

No difference in lithium content between planet-hosts and other stars.

Abstract

Parameters and abundances for 1002 stars of spectral types F, G, and K of luminosity class IV and V have been derived. After culling the sample for rotational velocity and effective temperature, 867 stars remain for discussion. Twenty-eight elements are considered in the analysis. The {\alpha}, iron-peak, and Period 5 transition metal abundances for these stars show a modest enhancement over solar averaging about 0.05 dex. The lanthanides are more abundant averaging about +0.2 dex over solar. The question is: Are these stars enhanced or is the Sun somewhat metal-poor relative to these stars? The consistency of the abundances derived here argues for the latter view. Lithium, carbon, and oxygen abundances have been derived. The stars show the usual lithium astration as a function of mass / temperature. There are more than 100 planet-hosts in the sample, and there is no discernible difference in their lithium content relative to the remaining stars. The carbon and oxygen abundances show the well-known trend of decreasing [x/Fe] ratio with increasing [Fe/H].