Study of The Abundance Patterns in The Metal-Poor Stellar Stream

TL;DR

This study investigates the chemical abundance patterns in metal-poor stellar stream stars to understand r-process nucleosynthesis and early Galaxy composition, revealing constant weak r-process yields and a metallicity-dependent main r-process contribution.

Contribution

It introduces an analysis of r-process component coefficients in stream stars, highlighting differences from r-rich stars and suggesting smaller progenitor masses for main r-process elements.

Findings

Weak r-process yields are nearly constant across stars.

Main r-process contribution increases with metallicity.

HD 237846 identified as a weak r-process star.

Abstract

The chemical abundances of the metal-poor stars in the stellar stream provide important information for setting constraints on models of neutron-capture processes. The study of these stars could give us a better understanding of r-process nucleosynthesis and chemical composition of the early Galaxy. Using the updated main r-process and weak r-process patterns, we fit abundances in the stellar stream stars. The weak r-process component coefficients are almost constant for the sample stars, including r-rich stars, which means that both weak r-process and Fe are produced as primary elements from SNeII and their yields have nearly a constant mass fraction. The difference between the stream stars and r-rich stars is obvious. For the stream stars, that the increase trend in the main r-process component coefficients as metallicity increases means the gradual increase in the production of main r-process elements relative to iron. This behavior implies that the masses of progenitors for the main r-process are smaller than those of the weak r-process. Furthermore, we find metal-poor stream star HD 237846 is a weak r-process star.