The relationship between the envelope composition of a 6M red-giant model and its future evolution.
Abstract
The questions regarding the maximum mass of a main-sequence star that becomes a white-dwarf; the mass of single white dwarfs; the enhanced abundance ratios of N/O and He/H in planetary nebulae and the He3 abundance in planetaries and in the interstellar medium are shown to be interrelated. We find that a model star of 6 Msun. on the main-sequence develops prior to the double-shell source phase a CO core of 0.82 Msun, an enrichment of 27% in the He/H ratio and a N/O ratio 5.5 times higher than the solar value. These results indicate that a 6 Msun star is a plausible planetary-nebula progenitor.
We also show that intermediate mass stars, ejecting most of their mass during the red-giant stage, are important contributors of C and 0 isotopes and of He3 to the interstellar medium.- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1980
- Bibcode:
- 1980A&A....88..127P
- Keywords:
-
- Red Giant Stars;
- Stellar Envelopes;
- Stellar Models;
- Abundance;
- Interstellar Matter;
- Main Sequence Stars;
- Planetary Nebulae;
- Stellar Evolution;
- Stellar Mass;
- Stellar Mass Ejection;
- Astrophysics