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

Journal Article · Sat Mar 01 04:00:00 EST 1986 · Astron. J.; (United States)

DOI:https://doi.org/10.1086/114042· OSTI ID:6282618

Brunish, W M; Gallagher, J S; Truran, J W

The problem of matching observed number ratios of blue to red supergiants (B/R) is re-examined on the basis of single-star evolution models which undergo helium ignition in the blue and self-consistently include mass loss. At lower luminosities (M/sub bol/> or approx. =-7.5), contamination of luminosity-selected red supergiant samples by intermediate-mass stars in the double-shell burning, asymptotic-giant-branch (AGB) phase is a problem. Using the spectroscopic data of Humphreys and McElroy on luminous Galactic supergiants, we find, after reasonable corrections for selection effects, that observed B/R ratios agree to better than a factor of 2 with those predicted by models. Additional uncertainties in B/R will be introduced by properties of real stellar populations and limitations in the models. Thus the theoretical and observed B/R ratios can be considered to agree to within expected errors, but more sensitive techniques are needed to provide sharp tests of stellar evolution theory. These methods include statistical distributions of stars on the H-R diagram and comparisons of luminosity functions for red and blue supergiants.

• Research Organization: Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 6282618
• Journal Information: Astron. J.; (United States), Journal Name: Astron. J.; (United States) Vol. 91:3; ISSN ANJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DIAGRAMS
GIANT STARS
HERTZSPRUNG-RUSSELL DIAGRAM
LUMINOSITY
MASS
MATHEMATICAL MODELS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STAR EVOLUTION
STAR MODELS
STARS
SUPERGIANT STARS