Bright Stars in the Galactic Globular M5

Abstract

We present a CCD investigation of the galactic globular M5 aimed to increase the statistical relevance of the available sample of evolving bright stars. Previous investigations, limited to the outer cluster region, have been extended toward the cluster center, more than doubling the number of observed luminous stars. On this basis, we discuss a statistically relevant sample, rich of 415 HB stars. The occurrence of a gap in the blue side of the HB is suggested. Comparison to the current evolutionary scenario discloses a good agreement concerning both the C-M diagram location and the relative abundance of stars in the advanced evolutionary phases, supporting our present knowledge of the evolution of low mass stars. Determination of the amount of the original helium content through the ratio R N(HB)/N(RGB) gives $Y=0.22\pm 0.02$.

16 pages, Standard TeX, 4 figures available upon request from [email protected]

Cited by in corpus (6)

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• Fe emission and ionized excess absorption in the luminous quasar 3C109 with XMM-Newton
• RR Lyrae variables in M5 as a test of pulsational theory
• UBV stellar photometry of bright stars in GC M5. I. UV colour-magnitude and colour-colour diagrams and some peculiarities in the HB stellar distribution
• Stellar Populations and Variable Stars in the Core of the Globular Cluster M5