Astrophysics and Space Science

, Volume 31, Issue 1, pp 3–10 | Cite as

Main sequence models for massive Zero-metal stars

  • Noel Cary
Article

Abstract

Zero-age main-sequence models for stars of 20, 10, 5 and 2M with no heavy elements are constructed for three different possible primordial helium abundances:Y=0.00,Y=0.23, andY=0.30. The latter two values ofY bracket the range of primordial helium abundances cited by Wagoner. With the exceptions of the two 20M models that contain helium, these models are found to be self-consistent in the sense that the formation of carbon through the triple-alpha process during pre-main sequence contraction is not sufficient to bring the CN cycle into competition with the proton-proton chain on the ZAMS. The zero-metal models of the present study have higher surface and central temperatures, higher central densities, smaller radii, and smaller convective cores than do the population I models with the same masses. If galaxies containing the zero-metal stars were formed as recently as one third the Hubble time, they would likely appear very blue today — perhaps bluer even that most known quasars — and their redshifted effective temperatures could range as high as 3×104 K to 4×104 K.

Keywords

Helium High Surface Central Temperature Small Radius Heavy Element 

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Copyright information

© D. Reidel Publishing Company 1974

Authors and Affiliations

  • Noel Cary
    • 1
  1. 1.Leander McCormick ObservatoryUniversity of VirginiaCharlottesvilleUSA

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