Detailed abundances in extremely metal poor dwarf stars extracted from SDSS

TL;DR

This study analyzes chemical abundances in extremely metal poor dwarf stars from SDSS, revealing diverse elemental enhancements and providing insights into early stellar populations.

Contribution

It presents detailed chemical abundance measurements of EMP stars using high-resolution spectroscopy and an automated analysis tool, expanding knowledge of early universe stellar compositions.

Findings

Detection of a C-rich, Mg-enhanced star ([Mg/Fe]=1.45)

Identification of Mn-rich stars ([Mn/Fe]>-0.4)

Discovery of Ni-rich stars ([Ni/Fe]>0.2)

Abstract

We report on the result of an ongoing campaign to determine chemical abundances in extremely metal poor (EMP) turn-off (TO) stars selected from the Sloan Digital Sky Survey (SDSS) low resolution spectra. This contribution focuses principally on the largest part of the sample (18 stars out of 29), observed with UVES@VLT and analyzed by means of the automatic abundance analysis code MyGIsFOS to derive atmosphere parameters and detailed compositions. The most significant findings include i) the detection of a C-rich, strongly Mg-enhanced star ([Mg/Fe]=1.45); ii) a group of Mn-rich stars ([Mn/Fe]>-0.4); iii) a group of Ni-rich stars ([Ni/Fe]>0.2). Li is measured in twelve stars, while for three upper limits are derived.