Beryllium abundances in metal-poor stars

TL;DR

This study measures beryllium in 25 metal-poor stars, confirming its increase with iron and oxygen, and suggests primary production with some intrinsic dispersion possibly due to inhomogeneous early galaxy enrichment.

Contribution

First detailed beryllium abundance analysis in metal-poor stars confirming its relation with Fe and O, supporting primary production models.

Findings

Be increases with Fe and O in metal-poor stars.

Be vs. O relation is linear with slope close to one.

Evidence of intrinsic dispersion in Be abundances at given metallicity.

Abstract

We have determined beryllium abundances for 25 metal-poor stars based on the high resolution and high signal-to-noise ratio spectra from the VLT/UVES database. Our results confirm that Be abundances increase with Fe, supporting the global enrichment of Be in the Galaxy. Oxygen abundances based on [O I] forbidden line implies a linear relation with a slope close to one for the Be vs. O trend, which indicates that Be is probably produced in a primary process. Some strong evidences are found for the intrinsic dispersion of Be abundances at a given metallicity. The deviation of HD132475 and HD126681 from the general Be vs. Fe and Be vs. O trend favours the predictions of the superbubble model, though the possibility that such dispersion originates from the inhomogeneous enrichment in Fe and O of the protogalactic gas cannot be excluded.