Evolution of Stars Containing ^{3}He
Abstract
Iben and Talbot have shown that the determination of stellar ages in NGC 2264 from gravitational- contraction times alone leads to the conclusion that many low-mass stars are up to 5 times older than the oldest stars of higher mass. Calculations show that 3He burning halts gravitational contraction along an evanescent main sequence roughly 2 mag above the normal main sequence. It is suggested that the apparent youth of the high-mass stars is due to 3He burning. An estimate of the age of NGC 2264 and the stars near the Orion Nebula from evolution of the upper main sequence and the gravitational ages of low-mass stars then yields an initial 2He abundance which is much larger than the 3He abundance in gas- rich meteorites. Envelopes of low-mass stars are a likely site for the formation of the 3He
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1971
- DOI:
- 10.1086/151061
- Bibcode:
- 1971ApJ...168...57U