Non-LTE analysis of massive O stars. III. The O 3 stars HD 93128, HD 93129A, and HDE 303308.
Abstract
Coudespectrograms of the eta-Carinae stars HD 93128: O3V (/f/), HD 93129A: O3If(asterisk), and HDE 303308: O3V (/f/) made on the 1.52-m ESO telescope in March 1978 and February 1980 at 3600-5000 A and reciprocal dispersion 12 A/mm, using baked IIIaJ-emulsion plates, are analyzed by the non-LTE methods described by Kudritzki (1980). Equivalent He I (4471-A) line widths, Balmer and He II line profiles, logarithmic plots of gravity vs effective temperature, theoretical evolutionary tracks, and the distance of the reference clusters Tr 14 and Tr 16 are used to calculate the respective star parameters: T(eff) = 48,000 + or - 3000, 45,000 + or - 2000, and 45,000 + or - 3000 K; g (cm/sec sq) = 3.85, 3.60, and 3.90 + or - 0.15 dex; mass = about 60 solar mass for all three stars; radius = 11 + or - 1, 21 + or - 2, and 13 + or - 2 solar radius; and log (L/solar L) = 5.7, 6.2, and 5.8 + or - 0.1. Hence the O3 stars are found to be cooler than was believed earlier, to have lost significant mass in the past, and to be placed nearer to the terminal age than to the zero age on the main sequence.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1983
- Bibcode:
- 1983A&A...125...34S
- Keywords:
-
- Nonequilibrium Thermodynamics;
- O Stars;
- Stellar Spectra;
- Stellar Temperature;
- Supermassive Stars;
- Atmospheric Models;
- Spectrograms;
- Stellar Evolution;
- Stellar Mass;
- Astrophysics;
- Line Profiles:O Stars;
- O Stars:Line Profiles;
- O Stars:Non-LTE Analyses