Galactic Chemical Evolution Signatures in Stellar Atmospheres and Their Possible Planetary Connection

Abstract

In recent years there have been many studies to determine whether there is a chemical signature in stellar atmospheres that can be linked to the presence of planets. Most of these studies have involved bulk analysis of stars to identify whether planet-hosting stars have a higher metallicity than non planet-hosting stars. These studies led to the work of Melendez et al. [49], which identified a signature in the solar photosphere which was likely caused by the presence of planets. To further explore this theory, I obtained high-quality spectra from the ESPaDOnS spectropolarimeter at the CFHT for 10 stars with similar stellar parameters (effective temperature, surface gravity, microturbulence velocity and metallicity). I performed a differential abundance analysis on the planet-hosting star 61 Vir against 9 comparison stars. This analysis indicated that there is no planetary signature present in 61 Vir but instead, that there is a signature observed when performing the same analysis on an individual star basis, which is observable with age. I determined the relative ages of the stars and then perform a differential abundance analysis of 9 stars using a younger tenth star as reference. From this I found likely evidence of galactic chemical evolution in the stellar atmospheres.