Detailed analyses of three neutron-capture-rich carbon-enhanced metal-poor stars

TL;DR

This study analyzes the chemical compositions of three very metal-poor, carbon-enhanced stars to understand neutron-capture nucleosynthesis processes, revealing diverse element enhancements and contributing to the knowledge of early stellar evolution.

Contribution

It provides detailed high-resolution abundance analyses of three CEMP stars, including detection of multiple neutron-capture elements, advancing understanding of nucleosynthesis in metal-poor stars.

Findings

Detection of s- and r-process elements in all stars

Identification of a star with third r-process peak elements

Diverse neutron-capture element patterns observed

Abstract

Approximately 20% of very metal-poor stars ([Fe/H] < -2.0) are strongly enhanced in carbon ([C/Fe] > +1.0). Such stars are referred to as carbon-enhanced metal-poor (CEMP) stars. We present a chemical abundance analysis based on high resolution spectra acquired with UVES at the VLT of three dwarf CEMP stars: SDSS J1349-0229, SDSS J0912+0216 and SDSS J1036+1212. These very metal-poor stars, with [Fe/H] < -2.5, were selected from our ongoing survey of extremely metal-poor dwarf candidates from the SDSS. Among these CEMPs, SDSS J1349-0229 has been identified as a carbon star ([C/O] > +1.0). First and second peak s-process elements, as well as second peak r-process elements have been detected in all stars. In addition, elements from the third r-process peak were detected in one of the stars, SDSS J1036+1212. We present the abundance results of these stars in the context of neutron-capture nucleosynthesis theories.