Population-I Pulsating Stars - Part Four - Period - Radius and Period - Gravity Relations
Abstract
The radiiR and surface gravitiesg of Population I pulsating stars (89 Delta Scuti-variables and 155 classical cepheids) have been investigated. Semi-empirical period-radius (P-R) and period-gravity (P-g) relations are obtained for Delta Scuti-stars (for the four lowest modes of radial pulsations) and for classical cepheids. For Delta Scuti-stars, the uncertainties of radius and gravity estimations calculated from theP-R andP-g relations for different modes, are evaluated. There is a good agreement both between theP-R relations and between theP-g relations for Delta Scuti-stars and for classical cepheids, but a ‘gap’ exists between the two types of variables. From models of Delta Scuti-stars, theoreticalP-R andP-g relations for the four lowest modes of radial pulsations are obtained, in a good agreement with the corresponding semi-empirical relations. There is an excellent agreement between the theoretical and semi-empirical period ratios of radial pulsations as derived from theP-R andP-g relations for Delta Scuti-stars. It is not necessary to take into account the colours (in addition to the periods), in order to estimate the radii and gravities of the variables under study.
- Publication:
-
Astrophysics and Space Science
- Pub Date:
- December 1988
- DOI:
- 10.1007/BF00641730
- Bibcode:
- 1988Ap&SS.150..357T
- Keywords:
-
- Stellar Gravitation;
- Stellar Oscillations;
- Stellar Physics;
- Variable Stars;
- Cepheid Variables;
- Periodic Variations;
- Stellar Color;
- Stellar Luminosity;
- Stellar Temperature;
- Astrophysics