Long-term photometry of RT lacertae: II. Further evidence for a circumstellar envelope and mass accretion


IBANOGLU C., PEKUNLU E. R. , KESKİN V. , TUNCA Z., EVREN M. S. , AKAN M. C. , ...Daha Fazla

ASTROPHYSICS AND SPACE SCIENCE, cilt.257, ss.83-93, 1998 (SCI İndekslerine Giren Dergi) identifier

  • Cilt numarası: 257 Konu: 1
  • Basım Tarihi: 1998
  • Dergi Adı: ASTROPHYSICS AND SPACE SCIENCE
  • Sayfa Sayıları: ss.83-93

Özet

The light curves, obtained by the authors of the present paper during the period 1978-1992, of the chromospherically active binary system RT Lac were examined. The average (B-V) colour indices were obtained and corrected for the interstellar extinction. Spectroscopic studies indicate that the less massive component may be taken as G8. The light curve analysis indicates that the less massive, larger component fills its corresponding Roche lobe. Both photometric and spectroscopic observations compel one to draw a conclusion that circumstellar matter does exist around the binary system. A colour excess caused by this matter is found to be 0.278 for B - V colour at mid-secondary eclipse. On the basis of photometric colour indices alone, the components of RT Lac are classified as G3-4 and G8. If we use the observed radial velocities of the less massive subgiant star from Ca II emission lines and from other optical lines we find for the mass of the more massive component as 1.34-1.70 M.. This mass range corresponds to the main sequence late F stars. The common envelope hypothesis and mass function and also blending of the spectral lines of more massive component point out that it should be at most a late F type main sequence star.