Delta Scuti variables - The link between giant- and dwarf-type pulsators
Abstract
An attempt is made to interpret the differences in pulsational behavior between horizontal branch and main sequence (or early post-main sequence) variables. Results of linear stability studies for delta Scuti stars are reviewed and supplemented with new calculations. The function of the opacity mechanism in generating instability to a variety of radial and nonradial modes is discussed. The highest excitation rates for these variables, though still much lower than in the case of Cepheids, are found in fundamental modes with higher spherical harmonic orders, l, and among higher overtones with low values of l. It is argued that amplitudes in delta Scuti stars are limited by nonlinear mode coupling, resulting in lower amplitudes and multiperiodicity, rather than by saturation of the opacity mechanism as is the case with horizontal branch variables.
- Publication:
-
Nonradial and Nonlinear Stellar Pulsation
- Pub Date:
- 1980
- DOI:
- Bibcode:
- 1980LNP...125...22D
- Keywords:
-
- Cepheid Variables;
- Dwarf Stars;
- Giant Stars;
- Main Sequence Stars;
- Opacity;
- Stellar Oscillations;
- Helium;
- Metallic Stars;
- Pulse Amplitude;
- Stellar Evolution;
- Stellar Gravitation;
- Variable Stars;
- Astrophysics