APOGEE Detection of N-rich stars in the tidal tails of Palomar 5

TL;DR

This study uses APOGEE data to identify nitrogen-rich stars in and beyond Palomar 5's tidal radius, confirming their origin from globular clusters and linking them to the Galactic halo.

Contribution

It provides the first evidence of N-rich stars in the tidal streams of Palomar 5, supporting their globular cluster origin and the chemical tagging approach.

Findings

N-rich stars are found within and beyond Palomar 5's tidal radius.

N-rich stars in tidal streams confirm globular cluster contribution to the Galactic halo.

Supports chemical tagging as a method to trace stellar origins.

Abstract

Recent results from chemical tagging studies using APOGEE data suggest a strong link between the chemical abundance patterns of stars found within globular clusters, and chemically peculiar populations in the Galactic halo field. In this paper we analyse the chemical compositions of stars within the cluster body and tidal streams of Palomar 5, a globular cluster that is being tidally disrupted by interaction with the Galactic gravitational potential. We report the identification of nitrogen-rich (N-rich) stars both within and beyond the tidal radius of Palomar 5, with the latter being clearly aligned with the cluster tidal streams; this acts as confirmation that N-rich stars are lost to the Galactic halo from globular clusters, and provides support to the hypothesis that field N-rich stars identified by various groups have a globular cluster origin.