Abundance ratios of volatile vs. refractory elements in planet-harbouring stars: hints of pollution?

TL;DR

This study examines the elemental abundance trends in planet-hosting stars compared to stars without planets, finding no significant pollution signatures but identifying a few stars with unusual abundance patterns.

Contribution

It provides a homogeneous analysis of volatile and refractory element abundances in a large sample of stars, testing for pollution signatures in planet hosts.

Findings

No significant abundance trend differences between stars with and without planets.

Most stars show a primordial origin of metallicity excess.

A few stars exhibit unusually high [X/H] vs. Tc slopes.

Abstract

We present the [X/H] trends as function of the elemental condensation temperature Tc in 88 planet host stars and in a volume-limited comparison sample of 33 dwarfs without detected planetary companions. We gathered homogeneous abundance results for many volatile and refractory elements spanning a wide range of Tc, from a few dozens to several hundreds kelvin. We investigate possible anomalous trends of planet hosts with respect to comparison sample stars in order to detect evidence of possible pollution events. No significant differences are found in the behaviour of stars with and without planets. This result is in agreement with a ``primordial'' origin of the metal excess in planet host stars. However, a subgroup of 5 planet host and 1 comparison sample stars stands out for having particularly high [X/H] vs. Tc slopes.