New high S/N observations of the Li-6/Li-7 blend in HD 84937 and two other metal-poor stars

TL;DR

This study presents high signal-to-noise ratio spectra of metal-poor stars, measuring lithium isotope ratios to assess primordial lithium abundance and compare with light element formation models.

Contribution

It provides precise measurements of Li-6/Li-7 ratios in metal-poor stars using high-resolution spectra, offering insights into primordial lithium and light element synthesis.

Findings

Li-6/Li-7 ratio in HD 84937 is 0.052 with sigma 0.019

Li-6 is undepleted or only moderately depleted in the star

Lithium depletion in the star is less than 0.1 dex

Abstract

High S/N ratio spectra have been obtained at CFHT at a spectral resolution of 100 000 for HD 84397 and two other metal poor stars. For HD 84 937, the S/N of 650 per pixel was obtained, yielding Li-6/Li-7 = 0.052 with a sigma of 0.019. The Li-6 abundance is compared with recent models of formation of light elements LiBeB. This comparison shows that Li-6 is either undepleted or only moderatly depleted in the star of interest. The depletion of Li-7 in this star is estimated to be less than 0.1 dex. The abundance of lithium on the Spite plateau accordingly can be takien as representative of the cosmological primordial lithium. See the joint paper astro-ph/9811327.