Stochastic stellar evolution. II. Fluctuations due to convection.
Abstract
A mechanism is described which simulates the random fluctuations of the convective elements in the outer convective zones of stars, and a comparison is made between solar models (with their oscillation properties) and observational data of the sun. The effect of statistical fluctuations on the oscillation periods is analyzed using a stochastic eigenvalue problem; it is shown that the width of the frequency lines is proportional to the amplitude of the stochastic fluctuations. In addition, the line broadening of the oscillation frequencies is several orders of magnitude smaller than the width observed by Hill et al. (1975) and Brown et al. (1978). Considering a fluctuation time scale comparable (or longer) to the thermal scale of the outer convective zones, the oscillatory properties of the star cannot follow the fluctuations in the mixing length, due to the thermal inertia of the outer layers. The present periods of the sun might therefore be interpreted as reminiscent of the sun's past fluctuation in the mixing length.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1979
- Bibcode:
- 1979A&A....79..261B
- Keywords:
-
- Solar Oscillations;
- Stellar Evolution;
- Stellar Models;
- Stochastic Processes;
- Calibrating;
- Hertzsprung-Russell Diagram;
- Solar Spectra;
- Astrophysics;
- Convection:Stellar Envelopes;
- Convection:Sun