Boron Abundances in the Galactic Disk

TL;DR

This study compiles boron abundance data in the Galactic disk, revealing its chemical evolution and linking it to primary and secondary production processes through observed abundance trends.

Contribution

It provides a comprehensive analysis of boron abundances in the Galactic disk and compares these with halo stars to understand boron's chemical evolution.

Findings

Boron abundance correlates with iron with a slope of 0.87.

Boron-oxygen relation has a steeper slope of ~1.5.

Smooth connection between halo and disk boron evolution.

Abstract

When compared to lithium and beryllium, the absence of boron lines in the optical results in a relatively small data set of boron abundances measured in Galactic stars to date. In this paper we discuss boron abundances published in the literature and focus on the evolution of boron in the Galaxy as measured from pristine boron abundances in cool stars as well as early-type stars in the Galactic disk. The trend of B with Fe obtained from cool F-G dwarfs in the disk is found to have a slope of 0.87 +/- 0.08 (in a log-log plot). This slope is similar to the slope of B with Fe found for the metal poor halo stars and there seems to be a smooth connection between the halo and disk in the chemical evolution of boron. The disk trend of boron with oxygen has a steeper slope of ~1.5. This slope suggests an intermediate behavior between primary and secondary production of boron with respect to oxygen. The slope derived for oxygen is consistent with the slope obtained for Fe provided that [O/Fe] increases as [Fe/H] decreases, as observed in the disk.