期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 477, 期 4, 页码 4565-4576出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/sty847
关键词
globular clusters; individual; ESO280-SC06
资金
- ARC LIEF grant from the Australian Research Council [LE130100104]
- Australian National University
- Swinburne University of Technology
- University of Queensland
- University of Western Australia
- University of Melbourne
- Curtin University of Technology
- Monash University
- Australian Astronomical Observatory
- Astronomy Australia Limited (AAL)
- Australian Government through the Commonwealth's Education Investment Fund (EIF)
- National Collaborative Research Infrastructure Strategy (NCRIS)
- National eResearch Collaboration Tools and Resources (NeCTAR)
- Australian National Data Service Projects (ANDS)
- University of Hawaii
- Pan-STARRS Project Office
- Max Planck Society
- Max Planck Institute for Astronomy
- Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching
- Johns Hopkins University
- Durham University
- University of Edinburgh
- Queen's University Belfast
- Harvard-Smithsonian Center for Astrophysics
- Las Cumbres Observatory Global Telescope Network Incorporated
- National Central University of Taiwan
- Space Telescope Science Institute
- National Aeronautics and Space Administration through the Planetary Science Division of the NASA Science Mission Directorate [NNX08AR22G]
- National Science Foundation [AST-1238877]
- University of Maryland
- Eotvos Lorand University (ELTE)
- Los Alamos National Laboratory
- Gordon and Betty Moore Foundation
- National Aeronautics and Space Administration
- National Science Foundation
We present the first spectroscopic observations of the very metal-poor Milky Way globular cluster ESO280-SC06. Using spectra acquired with the 2dF/AAOmega spectrograph on the Anglo-Australian Telescope, we have identified 13 members of the cluster, and estimate from their infrared calcium triplet lines that the cluster has a metallicity of [Fe/H] = -2.48(-0.11)(+0.06). This would make it the most metal-poor globular cluster known in the Milky Way. This result was verified with comparisons to three other metal-poor globular clusters that had been observed and analysed in the same manner. We also present new photometry of the cluster from EFOSC2 and SkyMapper and confirm that the cluster is located 22.9 +/- 2.1 kpc from the Sun and 15.2 +/- 2.1 kpc from the Galactic Centre, and has a radial velocity of 92.5(-1.6)(+2.4) km s(-1). These new data finds the cluster to have a radius about half that previously estimated, and we find that the cluster has a dynamical mass of the cluster of ( 12 +/- 2) x 10(3)M(circle dot). Unfortunately, we lack reliable proper motions to fully characterize its orbit about the Galaxy. Intriguingly, the photometry suggests that the cluster lacks a well-populated horizontal branch, something that has not been observed in a cluster so ancient or metal poor.
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