Horizontal Branch Morphology in Galactic Globular Clusters:Dense Environment is "A" Second Parameter

Abstract

view Abstract Citations (89) References (86) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Horizontal Branch Morphology in Galactic Globular Clusters:Dense Environment is "A" Second Parameter Buonanno, R. ; Corsi, C. ; Bellazzini, M. ; Ferraro, F. R. ; Pecci, F. Fusi Abstract The Horizontal Branch (HB) morphology in the color - magnitude diagram of the Galactic globular clusters depends on many factors, and it is now firmly established that the so-called "Second Parameter" is not just the cluster age as claimed for several years. As a part of a wider program devoted to the search for the physical processes driving the Horizontal Branch Morphology, we re-address here the problem of the extension of blue HB tails by introducing a new quantitative observable, \b, where B2=\{Number of HB stars with (B-V)_0<-0.02\}. We demonstrate that the environmental conditions within a cluster clearly affect its HB morphology, in the sense that, in general, the higher the cluster central density the higher is the relative number of stars populating the most blue region of its HB. Publication: The Astronomical Journal Pub Date: February 1997 DOI: 10.1086/118289 arXiv: arXiv:astro-ph/9611066 Bibcode: 1997AJ....113..706B Keywords: Astrophysics E-Print: 14 pages, AASTEX latex, plus 3 .eps figures automatically enclosed, needs the latex-macros aj_pt4.sty and epsf.sty -- To appear on The Astronomical Journal, february 1996 issue full text sources arXiv | ADS | data products SIMBAD (62)