A Double Main Sequence in the Globular Cluster NGC 6397

Bibcode
2012ApJ...745...27M
DOI
10.1088/0004-637X/745/1/27
Milone, A. P.; Marino, A. F.; Piotto, G.; Bedin, L. R.; Anderson, J.; Aparicio, A.; Cassisi, S.; Rich, R. M.
Bibliographical reference

The Astrophysical Journal, Volume 745, Issue 1, article id. 27 (2012).

Advertised on:
1
2012
Journal
The Astrophysical Journal
Number of authors
8
IAC number of authors
2
Citations
92
Refereed citations
87
Description
High-precision multi-band Hubble Space Telescope (HST) photometry reveals that the main sequence of the globular cluster NGC 6397 splits into two components, containing ~30% and ~70% of the stars. This double sequence is consistent with the idea that the cluster hosts two stellar populations: (1) a primordial population that has a composition similar to field stars, containing ~30% of the stars, and (2) a second generation with enhanced sodium and nitrogen, depleted carbon and oxygen, and a slightly enhanced helium abundance (ΔY ~ 0.01). We examine the color difference between the two sequences across a variety of color baselines and find that the second sequence is anomalously faint in m F336W. Theoretical isochrones indicate that this could be due to NH depletion. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.
Related projects
NGC 2808 Globular Cluster
Milky Way and Nearby Galaxies

The general aim of the project is to research the structure, evolutionary history and formation of galaxies through the study of their resolved stellar populations, both from photometry and spectroscopy. The group research concentrates in the most nearby objects, namely the Local Group galaxies including the Milky Way and M33 under the hypothesis

Martín
López Corredoira
Closed
Type
Refereed
The Milky Way and the Local Group (MWLG)

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