Bibcode
Milone, A. P.
Bibliographical reference
Memorie della Societa Astronomica Italiana, v.84, p.79 (2013)
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2013
Citations
3
Refereed citations
2
Description
The horizontal branch (HB) morphology of globular clusters (GCs) is
mainly described by metallicity. The fact that some clusters with almost
the same metallicity exhibit different HB demonstrates that other
parameters are at work. We present results from the analysis of the CMD
of 72 GCs obtained with the Advanced Camera for Survey (ACS) of the
Hubble Space Telescope (HST). We find a significant correlation between
the HB color extension and the mass of the hosting cluster, while the
color distance between the HB and the red-giant branch (RGB) depends on
metallicity and age. We suggest that age and metallicity are the main
global parameters of the HB morphology in GCs, while the HB extension is
mainly due to internal helium variation, associated to multiple
populations.