Ultraviolet colours of main-sequence stars
Abstract
The five-band ultraviolet photometer in ANS is described, and the data reduction procedures are presented. Data on 182 slightly reddened main-sequence stars, and on 56 giants and supergiants are discussed. For main-sequence stars average intrinsic ultraviolet colors are derived with an accuracy of a few hundredth of a magnitude. The color indices ultraviolet-visual of supergiants are clearly redder than main-sequence stars in the spectral type ranges B0 to B7 and A3 to F0, but are similar from about B7 to A0. Giants are slightly redder than main-sequence stars at most spectral types. A comparison with Kurucz's (1975) fully line-blanketed models shows that the early-type supergiants are 0.5 to 1 mag redder than the models, but the later-type supergiants are well described. For the main-sequence stars this comparison (normalization at B3V) has as main results: ultraviolet colors of O stars are bluer by 0.1 to 0.3 mag, those of A0V to F0V stars are redder with a maximum around A2V of 0.2 mag, and those of F5V to F8V stars are 3 mag bluer at 1,550 A than the model colors.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1980
- Bibcode:
- 1980A&A....85..221W
- Keywords:
-
- Astronomical Netherlands Satellite;
- Main Sequence Stars;
- Stellar Spectrophotometry;
- Ultraviolet Photometry;
- Data Reduction;
- Giant Stars;
- Interstellar Extinction;
- O Stars;
- Qualitative Analysis;
- Spectrum Analysis;
- Stellar Evolution;
- Supergiant Stars;
- Astronomy