MULTIPLE STELLAR POPULATIONS IN THE GALACTIC GLOBULAR CLUSTER NGC 6752
- Dipartimento di Astronomia, Universita di Padova, Vicolo dell'Osservatorio 3, I-35122 Padova (Italy)
- Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States)
- Space Telescope Science Institute, 3800 San Martin Drive, Baltimore, MD 21218 (United States)
- Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova (Italy)
- Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)
We have carried out high-precision photometry on a large number of archival Hubble Space Telescope images of the Galactic globular cluster NGC 6752, to search for signs of multiple stellar populations. We find a broadened main sequence (MS) and demonstrate that this broadening cannot be attributed either to binaries or to photometric errors. There is also some indication of an MS split. No significant spread could be found along the sub-giant branch, however. Ground-based photometry reveals that in the U versus (U - B) color-magnitude diagram the red-giant branch (RGB) exhibits a clear color spread, which we have been able to correlate with variations in Na and O abundances. In particular, the Na-rich, O-poor stars identified by Carretta et al. define a sequence on the red side of the RGB, while Na-poor, O-rich stars populate a bluer, more dispersed portion of the RGB.
- OSTI ID:
- 21392277
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 709; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Galactic globular cluster NGC 6752 and its stellar population as inferred from multicolor photometry
AGB sodium abundances in the globular cluster 47 Tucanae (NGC 104)