Implications of helium diffusion for globular cluster isochrones and luminosity functions

Abstract

view Abstract Citations (88) References (49) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Implications of Helium Diffusion for Globular Cluster Isochrones and Luminosity Functions Proffitt, Charles R. ; Vandenberg, Don A. Abstract This study presents grids of evolutionary sequences for masses from 0.5 and 1.0 solar mass and Fe/H metallicities of -2.26, -1.26, and -0.65 computed both with and without the inclusion of diffusion. These are interpolated to produce isochrones, for ages from 10 to 18 Gyr, and associated luminosity functions, for several power-law mass functions. The resultant age-luminosity relations indicate that the gravitational settling of helium can reduce the age at a given turnoff luminosity by about 10 percent, with considerably larger effects on turnoff temperatures and colors. Differences in the shapes of the luminosity functions from canonical models and those which included diffusion were found to be so small as to be observationally undetectable. Extensive tables of tracks, isochrones, and luminosity functions are provided. Publication: The Astrophysical Journal Supplement Series Pub Date: December 1991 DOI: 10.1086/191614 Bibcode: 1991ApJS...77..473P Keywords: Globular Clusters; Helium; Stellar Evolution; Stellar Luminosity; Abundance; Diffusion; Stellar Interiors; Astrophysics; CLUSTERS: GLOBULAR; DIFFUSION; STARS: ABUNDANCES; STARS: EVOLUTION; STARS: INTERIORS full text sources ADS | data products SIMBAD (4) CDS (1)