The Arcturus Moving Group: Its Place in the Galaxy

TL;DR

The paper investigates the Arcturus moving group, analyzing its chemical composition and kinematic properties to understand its origin, whether from a dissolved cluster, accreted satellite, or dynamical processes within the Galaxy.

Contribution

It provides a comprehensive spectroscopic analysis of the group and confirms its existence across multiple surveys, challenging existing theories about its origin.

Findings

Chemically similar to disk stars with no clear homogeneity

Confirmed the group's existence using multiple surveys

Origin remains unresolved, consistent with both dynamical and merger scenarios

Abstract

The Arcturus moving group is a well-populated example of phase space substructure within the thick disk of our Galaxy. Traditionally regarded as the remains of a dissolved open cluster, it has recently been suggested to be a remnant of a satellite accreted by our Galaxy. To investigate the origin of the group we undertook a high-resolution spectroscopic abundance study of Arcturus group members and candidates. Examining abundance of Fe, Mg, Ca, Ti, Cr, Ni, Zn, Ce, Nd, Sm and Gd for 134 stars we found that the group is chemically similar to disk stars and does not exhibit a clear chemical homogeneity. Furthermore, we confirm the existence of the Arcturus group using the Nordstroem et al. (2004), Schuster et al. (2006) and RAdial Velocity Experiment (RAVE) surveys (Steinmetz et al. 2006). The origin of the group still remains unresolved: the chemical results are consistent with a dynamical origin but do not entirely rule out a merger one. Certainly, the Arcturus group provides a challenge to our understanding of the nature and origin of the Galaxy's thick disk.