On the blue stragglers and horizontal branch morphology in Galactic globular clusters - Some speculations and a new working scenario

Abstract

view Abstract Citations (147) References (97) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the Blue Stragglers and Horizontal Branch Morphology in Galactic Clusters: Some Speculations and a New Working Scenario Fusi Pecci, F. ; Ferraro, F. R. ; Corsi, C. E. ; Cacciari, C. ; Buonanno, R. Abstract The current status of the search and study of Blue Stragglers (BSS) in Galactic globular clusters is reviewed leading to a catalog of 425 BSS- candidates in 21 clusters. A new interpretative scenario is presented, based on the claimed detection of a BSS-progeny located on the red Horizontal Branch (HB) in the various clusters, as first suggested by Renzini and Fusi Pecci (1988, ARA&A, 26,199) for M3. The cluster concentration and integrated luminosity are important driving parameters when considering the properties of the BSS population and HB morphology, now partially connected to each other. Implications and problems emerged within the framework of cluster stellar evolution are discussed and some speculations are presented. BSS luminosity functions (LF) are also presented and discussed. Though selection effects and poor statistics still dominate the available database, the total BSS LF shows a clear peak at M_V_~+3.2 and the brightest BSS are about 2.5 mag brighter than the corresponding turnoff stars. Concerning the BSS location with respect to the extension of the zero age main sequence (ZAMS) and its dependence on metallicity, the BSS sequence always has a much larger intrinsic width than expected from photometric errors and is systematically shifted towards the red with respect to the ZAMS. This redward shift appears to be slightly related with metallicity. Finally, a preliminary analysis of the population ratios between detected BSS in a cluster, N_BSS_, and their claimed progeny on the HB, N^HB^_BSP_, leads to N_BSS_/N^HB^_BSP_~6. Publication: The Astronomical Journal Pub Date: November 1992 DOI: 10.1086/116361 Bibcode: 1992AJ....104.1831F Keywords: Globular Clusters; Horizontal Branch Stars; Morphology; Stellar Evolution; Astronomical Catalogs; Milky Way Galaxy; Stellar Luminosity; Astrophysics; GLOBULAR CLUSTERS: GENERAL; STARS: MAIN SEQUENCE; STARS: EARLY TYPE full text sources ADS | data products SIMBAD (190) NED (5)