Issue |
Astron. Astrophys. Suppl. Ser.
Volume 137, Number 2, June I 1999
|
|
---|---|---|
Page(s) | 217 - 221 | |
DOI | https://doi.org/10.1051/aas:1999485 | |
Published online | 15 June 1999 |
Photometry and spectroscopy of the RS CVn system σ Geminorum
1
Beijing Astronomical Observatory, Chinese Academy of Sciences, Bejing 100101, China
2
Chinese Academy of Sciences-Peking University joint Beijing Astrophysical Center, Beijing 100871, China
Send offprint request to: X.B. Zhang
Received:
22
July
1998
Accepted:
31
August
1998
We present new UBV photoelectric photometry and high-resolution H spectroscopy of the RS CVn system σ Gem made in 1993-1994. A brief photometric analysis for the new light curves is carried out using the Wilson-Devinney method with spot approximation based on the Roche model. The result suggests the probable presence of two cool spots on the K1 III primary around the phases of and . The spot activity is discussed in connection with the chromospheric H emission. The enhanced H core emission is found to vary with phase and shows distinct anti-correlation with the spot regions. It may be an indication for the existence of plage regions on σ Gem.
Key words: stars: σ Gem; activity / binaries: close
© European Southern Observatory (ESO), 1999