| |
 |
| Paper: |
A Calibration of Stellar Parameters for A and F Stars |
| Volume: |
349, Astrophysics of Variable Stars |
| Page: |
285 |
| Authors: |
Lorenz, D.; Breger, M.; Pamyatnykh, A. |
| Abstract: |
We discuss the determination of effective temperatures and surface gravities of A and F stars using Stroemgren photometric indices. We use synthetic colours from the model atmospheres of Smalley & Kupka(1997) to build a grid and determine the theoretical values of Teff and log g. Subsequently, we calibrate the photometric indices in the grid by using a set of stars with well determined empirical and semi-empirical temperatures and surface gravities. For most of the stars either temperature or surface gravity measurements are available but not both. Since the first calibrations in the 1970s the number of stars with measured temperatures has increased. However, the number of log g measurements has not increased correspondingly. For this reason we calculated log g using HIPPARCOS parallaxes to determine luminosities and evolutionary mass tracks according to the basic relations g ∝ M⁄R2 and R2 ∝ L⁄T4eff . This method has been applied to all our sets of temperature calibration stars in order to increase the number of log g values. Furthermore we used empirical values of log g from double-star systems. Finally, we present our results and compare them with other calibrations. |
|
|
|
|
|
