Astrophysical Origins for the Unusual Chemical Abundance of the Globular Cluster Palomar 1

TL;DR

This study investigates the unique chemical abundance patterns in globular cluster Palomar 1, suggesting they result from a top-light initial mass function, differing from typical disk star compositions.

Contribution

It provides a detailed chemical abundance analysis of Palomar 1 and proposes a top-light IMF as the explanation for its unusual chemical signatures.

Findings

Palomar 1 has higher SNe Ia and s-process element abundances than disk stars.

The primary component contributions to Pal 1 are smaller than those to disk stars.

A top-light IMF can explain Palomar 1's distinctive chemical abundance pattern.

Abstract

We study the abundances of {\alpha} elements, Fe-peak elements, and neutron-capture elements in Pal 1. We found that the abundances of the SNe Ia and main s-process components of Pal 1 are larger than those of the disk stars and the abundances of the primary component of Pal 1 are smaller than those of the disk stars with similar metallicity. The Fe abundances of Pal 1 and the disk stars mainly originate from the SNe Ia and the primary component, respectively. Although the {\alpha} abundances dominantly produced by the primary process for the disk stars and Pal 1, the contributions of the primary component to Pal 1 are smaller than the corresponding contributions to the disk stars. The Fe-peak elements V and Co mainly originate from the primary and secondary components for the disk stars and Pal 1, but the contributions of the massive stars to Pal 1 are lower than those of the massive stars to the disk stars. The Yabundances mainly originate from the weak r-component for the disk stars. However, the contributions of the main s-components and main r-components to Y are close to those of the weak r-component for Pal 1. The Ba abundances of Pal 1 and the disk stars mainly originate from the main s-component and the main r-component, respectively. Our calculated results imply that the unusual abundances of Pal could be explained by the top-light IMF for Pal 1 progenitor-system.