A Conjecture Regarding the Evolution of Dwarf Stars into Red Giants
Abstract
The conjecture that a barytrope with local nonconstant polytropic index n(r) is always less centrally condensed than the polytrope whose constant index nm is max n(r), with nm less than five, is investigated. The conjecture is consistent with numerical results for 2 million different barytropes. Although no exceptions are found, a proof of the conjecture is not found, except in a somewhat weaker form. It is determined that in normal low-mass red giants, with degenerate helium cores, the cause of the high degree of central condensation is the molecular weight gradient in the hydrogen-burning shell, along with the thin isothermal nondegenerate helium shell sandwiched between the hydrogen-burning shell and the degenerate bulk of the helium core. Although the symptoms of a red giant manifest themselves in the envelope outside the burning shell, the underlying cause is to be found further in.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1991
- DOI:
- 10.1086/170833
- Bibcode:
- 1991ApJ...383..757E
- Keywords:
-
- Dwarf Stars;
- Red Giant Stars;
- Stellar Evolution;
- Stellar Interiors;
- Computational Astrophysics;
- Polytropic Processes;
- Stellar Envelopes;
- Stellar Mass;
- Astrophysics;
- STARS: EVOLUTION;
- STARS: INTERIORS