1994/07/21 by V. Castellani, S. Degl'Innocenti, S. degl'Innocenti +1 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Scientific Research and Discoveries #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/175780
postscript file of 10 pages plus 1 tables,rep.1 5 figures will be added later as postscript file The tex file and the other two not postscript figures are available upon request at [email protected], rep.1
arxiv created 1994/07/21 · openalex publication_date 1995/06/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
In this paper we investigate the hot end of the horizontal branch (HB), presenting evolutionary constraints concerning the C-M diagram location and the gravity of hot HB stars. According to the adopted evolutionary scenario, we predict an upper limit for HB temperatures of about log T<SUB>e</SUB> = 4A5, remarkably cooler than previous estimates. We find that such a theoretical prescription appears in good agreement with available observational data concerning both stellar temperatures and gravities. Finally, the problem of gaps in the HB distribution is discussed, suggesting that, at least in the case of the cluster NGC 6752, evolutionary gaps, a bimodal distribution of CNO, and stellar rotation should all play a negligible role.