The galactic globular cluster system - Calibration of the ratio R = N(HB)/N(RGB)

Bibcode
1987A&A...183..228C
Caputo, F.; Martinez Roger, C.; Paez, E.
Referencia bibliográfica

Astronomy and Astrophysics (ISSN 0004-6361), vol. 183, no. 2, Sept. 1987, p. 228-233.

Fecha de publicación:
9
1987
Número de autores
3
Número de autores del IAC
2
Número de citas
66
Número de citas referidas
59
Descripción
On the basis of Synthetic Horizontal Branches computed with Sweigart and Gross (1976) Horizontal Branch evolutionary tracks, and by means of Sweigart and Gross (1978) Red Giant Branch star models, the calibration of the ratio R = N(HB)/N(RGB) in terms of helium abundance (Y), He-core mass (Mc) and Horizontal Branch morphology is derived. The results obtained in the present paper confirm that the estimate for Y is independent of the Horizontal Branch morphology, at least within the observed range of R-values and for clusters containing RR Lyrae variables. As far as the occurrence of enhanced He-core mass is concerned, the resulting estimate for Y increases by dY/dΔMc = 0.40. From star counts in some well studied RR Lyrae rich globular clusters a mean value for Y equal to 0.24±0.01 is obtained.
Tipo
Con árbitro
Estrellas variables

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