Diffusion of a strong internal magnetic field through the radiative envelope of a 2.25 M sun-star.
Abstract
Summary. Strong internal magnetic fields of stars are probably relevant for triggering supernova explosions, pulsar and white dwarf magnetic fields and the fields of some magnetic stars. We present numerical calculations for the evolution of a magnetic field produced by turbulent dynamo action in the convective core of a 2.25 M0- star. The diffusion of the field through the radiative envelope is investigated. The field reaches detectable surface values in a time less than 1 % of the familiar magnetic timescale T = R2. -1. For stars with M Mc (Mc = 2.25.. .5 M0 depending on the core field strength) the diffusion time is less than or at most of the order of the main sequence lifetime. Consequently, a core dynamo can serve as a model for magnetic stars in the mass range 1.5 M0 M Mc. Stars with 1.2 M0 M 1.5 M0 probably possess a field which is a remnant from dynamo action during the Hayashi phase. Stars with M Mc have main sequence lifetimes too short to allow for growing of a detectable surface field. Their hidden fields are required, however, for the production of the observed pulsar magnetic fields. Key words: stars - magnetic field - stellar structure and evolution - a-effect - dynamo-theory
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1978
- Bibcode:
- 1978A&A....68...57S
- Keywords:
-
- Dynamo Theory;
- Stellar Envelopes;
- Stellar Evolution;
- Stellar Interiors;
- Stellar Magnetic Fields;
- Stellar Structure;
- Magnetic Diffusion;
- Pulsars;
- Stellar Mass;
- Supernovae;
- White Dwarf Stars;
- Astrophysics;
- Dynamo Theory:Stellar Models;
- Magnetic Fields:Stellar Evolution