Measuring Be depletion in cool stars with exoplanets

TL;DR

This study investigates beryllium depletion in cool stars with planets, revealing enhanced depletion at lower temperatures and suggesting planetary formation processes influence stellar light element abundances.

Contribution

It provides the first evidence of Be depletion differences in cool planet-hosting stars compared to similar stars without planets.

Findings

Be depletion increases in cooler stars.

Cool planet hosts show 0.25 dex more Be depletion.

Depletion may be linked to planetary system formation processes.

Abstract

We present new UVES spectra of a sample of 14 mostly cool unevolved stars with planetary companions with the aim of studying possible differences in Be abundance with respect to stars without detected planets. We determine Be abundances for these stars that show an increase in Be depletion as we move to lower temperatures. We carry out a differential analysis of spectra of analog stars with and without planets to establish a possible difference in Be content. While for hot stars no measurable difference is found in Be, for the only cool (Teff ~ 5000 K) planet host star with several analogs in the sample we find enhanced Be depletion by 0.25 dex. This is a first indication that the extra-depletion of Li in solar-type stars with planets may also happen for Be, but shifted towards lower temperatures (Teff < 5500 K) due to the depth of the convective envelopes. The processes that take place in the formation of planetary systems may affect the mixing of material inside their host stars and hence the abundances of light elements.