Affiliation:
1. Kapteyn Astronomical Institute, University of Groningen , Landleven 12, NL-9747 AD Groningen, the Netherlands
2. Astronomisches Rechen-Institut , Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg, Germany
3. Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna , Via Gobetti 93/2, I-40129, Bologna, Italy
Abstract
ABSTRACT
Dynamically cold stellar streams are the relics left over from globular cluster dissolution. These relics offer a unique insight into a now fully disrupted population of ancient clusters in our Galaxy. Using a combination of Gaia eDR3 proper motions, optical and near-UV colours, we select a sample of likely Red Giant Branch stars from the GD-1 stream for medium-low resolution spectroscopic follow-up. Based on radial velocity and metallicity, we are able to find 14 new members of GD-1, 5 of which are associated with the spur and blob/cocoon off-stream features. We measured C-abundances to probe for abundance variations known to exist in globular clusters. These variations are expected to manifest in a subtle way in globular clusters with such low masses ($\sim 10^4\,{\rm ~\textrm {M}_\odot }$) and metallicities ([Fe/H] ∼ −2.1 dex). We find that the C-abundances of the stars in our sample display a small but significant (3σ level) spread. Furthermore, we find ∼3σ variation in Mg-abundances among the stars in our sample that have been observed by APOGEE. These abundance patterns match the ones found in Galactic globular clusters of similar metallicity. Our results suggest that GD-1 represents another fully disrupted low-mass globular cluster where light-element abundance spreads have been found.
Funder
NWO
NASA
Space Telescope Science Institute
Klaus Tschira Foundation
European Space Agency
Alfred P. Sloan Foundation
National Science Foundation
U.S. Department of Energy
Office of Science
University of Arizona
Brookhaven National Laboratory
Carnegie Mellon University
University of Florida
Harvard University
Johns Hopkins University
Lawrence Berkeley National Laboratory
New Mexico State University
New York University
Ohio State University
Pennsylvania State University
University of Portsmouth
Princeton University
University of Tokyo
University of Utah
Vanderbilt University
University of Virginia
University of Washington
Yale University
Chinese Academy of Sciences
National Development and Reform Commission
Science and Technology Facilities Council
European Research Council
Publisher
Oxford University Press (OUP)
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
4 articles.
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