Four Metal-poor Stars in the Sagittarius Dwarf Spheroidal Galaxy
Name
Chiti_2019_ApJ_875_112.pdf
Description
Published version
Size
2.81 MB
Format
Adobe PDF
Checksum (MD5)
f36ad38ac53d6ece28fc02c20dff64b9
Author(s)
Chiti, Anirudh
Frebel, Anna L.
Date Issued
April 2019
Journal
Astrophysical Journal
Publisher
American Astronomical Society
Citation
Chiti, Anirudh and Anna Frebel. "Four Metal-poor Stars in the Sagittarius Dwarf Spheroidal Galaxy." Astrophysical Journal 875, 2 (April 2019): 112 © 2019 American Astronomical Society
Version
Final published version
Abstract
All rights reserved. We present the metallicities and carbon abundances of four newly discovered metal-poor stars with -2.2 < [Fe/H] < -1.6 in the Sagittarius dwarf spheroidal galaxy. These stars were selected as metal-poor member candidates using a combination of public photometry from the SkyMapper Southern Sky Survey and proper-motion data from the second data release from the Gaia mission. The SkyMapper filters include a metallicity-sensitive narrowband v filter centered on the Ca ii K line, which we use to identify metal-poor candidates. In tandem, we use proper-motion data to remove metal-poor stars that are not velocity members of the Sagittarius dwarf spheroidal galaxy. We find that these two data sets allow for efficient identification of metal-poor members of the Sagittarius dwarf galaxy to follow up with further spectroscopic study. Two of the stars we present have [Fe/H] < -2.0, which adds to the few other such stars currently identified in the Sagittarius dwarf galaxy that are likely not associated with the globular cluster M54, which resides in the nucleus of the system. Our results confirm that there exists a very metal-poor stellar population in the Sagittarius dwarf galaxy. We find that none of our stars can be classified as carbon-enhanced metal-poor stars. Efficiently identifying members of this population will be helpful to further our understanding of the early chemical evolution of the system.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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Persistent DSpace Link
DOI of Published Version
https://doi.org/10.3847/1538-4357/AB0F9F
