A study of visual double stars with early-type primaries. V. Post-T Tauri secondaries.
Abstract
In the previous articles of this series about 100 secondaries were found to be physical companions to O and B type primaries. The majority of the secondaries are of spectral type F, G or K and in the present work their properties are investigated in relation to their evolutionary status. The ages of the systems have been determined from uvbyβ photometry of the primaries and it is found that all are younger than 150 million years and that half of them are less than 30 million years old. More than 50% of the F, G and K secondaries exhibit spectroscopic features (Ca II H, K and Hα emission and strong lithium absorption) typical of young stars and reminiscent of T Tauri stars although not as conspicuous. Also, in contrast to the T Tauri stars they do not possess any significant infrared or ultraviolet excess emission and they only show a small degree of variability. These properties and the fact that they are older and lie closer to the ZAMS make it appropriate to classify them as post-T Tauri stars.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1986
- Bibcode:
- 1986A&A...156..223L
- Keywords:
-
- Binary Stars;
- Early Stars;
- Stellar Evolution;
- Visible Spectrum;
- Hertzsprung-Russell Diagram;
- Infrared Spectra;
- Radiant Flux Density;
- Stellar Luminosity;
- Stellar Spectrophotometry;
- T Tauri Stars;
- Tables (Data);
- Astrophysics