Blue-to-red ratios as tests for theoretical models of massive stars

Abstract

view Abstract Citations (33) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Blue-to-red ratios as tests for theoretical models of massive stars Brunish, W. M. ; Gallagher, J. S. ; Truran, J. W. Abstract The problem of matching observed number ratios of blue to red supergiants (B/R) is examined within the framework of a single star-evolution model which undergoes helium ignition in the blue and is self-consistent with respect to mass loss. It is shown that the completeness of surveys of luminous blue and red supergiants has improved in the past few years by a factor of at least two. However, B/R ratios are still uncertain due to selection effects, uncertainties in the bolometric correction, and temperature conversions in hot stars. At low bolometric luminosities, M(bol) less than about 7.5 AGB stars may be contaminating the massive red supergiant sample. Observed B/R ratios for lower-metallicity regions of the Galaxy and the Magellanic Clouds, may still show significant incompleteness effects. In addition, the presence of Wolf-Rayet (W-R) stars and binaries may also contribute to the uncertainty. Methods for adjusting the mass loss rates estimates in order to reproduce the observed distribution of stars between the ZAMS and the Hertzsprung gap are described. Publication: The Astronomical Journal Pub Date: March 1986 DOI: 10.1086/114042 Bibcode: 1986AJ.....91..598B Keywords: Blue Stars; Mass Ratios; Red Giant Stars; Stellar Evolution; Stellar Models; Supergiant Stars; Asymptotic Giant Branch Stars; Hertzsprung-Russell Diagram; Stellar Mass; Stellar Mass Ejection; Wolf-Rayet Stars; Astrophysics full text sources ADS |