Bibcode
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).
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1
2012
Journal
Citations
97
Refereed citations
91
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
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