Open AccessGalactic globular clusters as a test for very‐low‐mass stellar models
Author(s) -
Cassisi S.,
Castellani V.,
Ciarcelluti P.,
Piotto G.,
Zoccali M.
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03457.x
Subject(s) - physics , globular cluster , astrophysics , metallicity , luminosity , stars , cluster (spacecraft) , star cluster , open cluster , main sequence , hertzsprung–russell diagram , horizontal branch , stellar mass , galaxy , stellar evolution , astronomy , star formation , computer science , programming language
We make use of the ‘Next Generation’ model atmospheres of Allard et al. and Hauschildt, Allard & Baron to compute theoretical models for low‐ and very‐low‐mass stars for selected metallicities in the range Z =0.0002 to 0.002. On this basis, we present theoretical predictions covering the sequence of H‐burning stars as observed in Galactic globulars from the faint end of the main sequence up to, and beyond, the cluster turn‐off. The role played by the new model atmospheres is discussed, showing that present models appear in excellent agreement with models by Baraffe et al. as computed on a quite similar physical basis. One finds that the theoretical mass–luminosity relations based on this updated set of models are in good agreement with the empirical data provided by Henry & McCarthy. Comparison with HST observation discloses that the location on the colour–magnitude diagram of the lower main sequence in Galactic globular clusters appears again in good agreement with the predicted sensitive dependence of these sequences on the cluster metallicity.