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On the effects of cluster density and concentration on the horizontal branch morphology - The origin of the blue tailsPossible relationships between horizontal branch (HB) morphology in Galactic globular clusters and the cluster structure and dynamical evolution are investigated. New HB observables are defined and determined using a theoretical framework deduced from HB models. Data for 53 Galactic globular clusters are used to obtain correlations between the observables. It is found that the net length of the HB and the presence and extent of blue tails in particular are correlated with the cluster density and concentrations, in the sense of more concentrated or denser clusters having bluer and longer HB morphologies. This effect is especially strong for the intermediate metallicity clusters. Thus, the cluster environment can affect the stellar evolution leading to the HB and therefore the HB morphology. This result is interpreted in terms of an enhanced mass removal from the HB progenitors.
Document ID
19930046184
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Fusi Pecci, F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Ferraro, F. R. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Bellazzini, M. (Osservatorio Astronomico Bologna, Italy)
Djorgovski, S. (California Inst. of Technology Pasadena, United States)
Piotto, G. (Padova, Univ. Padua, Italy)
Buonanno, R. (Osservatorio Astronomico di Monte Mario Rome, Italy)
Date Acquired
August 16, 2013
Publication Date
March 1, 1993
Publication Information
Publication: Astronomical Journal
Volume: 105
Issue: 3
ISSN: 0004-6256
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NAG5-1173
CONTRACT_GRANT: NAS5-31348
CONTRACT_GRANT: NSF AST-91-57412
Distribution Limits
Public
Copyright
Other