Evolution of Massive Pregalactic Stars - Part Two - Nucleosynthesis in Pair Creation Supernovae and Pregalactic Enrichment
Abstract
The final evolution of Population III stars (zero metal stars) having large masses (M ≧ 80 Msun) is considered. Stellar cores consisting mainly of carbon and oxygen obtained from quasistatic calculations are evolved through the e- e+ -pair creation instability. Hydrodynamical computations of the collapse and the supernova explosion (pair creation supernova: PCSN) coupled to a network of nuclear reactions are presented. Carbon-oxygen core masses between 48 and 112 Msun are found to explode, corresponding to an initial mass range 100 < Mι/Msun ≲ 220 Msun. The nucleosynthesis products in PCSN due to incomplete explosive oxygen burning are calculated. Elements in the range carbon to calcium are produced, and no iron-peak elements result in the PCSN process. The enrichment of the pregalactic gas due to the combined effect of steady mass loss and the PCSN explosion is estimated. It appears that only a small fraction (about 10-4) of the gas is processed through the Population III stars of large masses, if the resulting heavy element enrichment is constrained to the minimum metallicity (∼ 10-5) observed in extreme Population II stars.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1983
- Bibcode:
- 1983A&A...119...61O