Astron. Astrophys. 319, 886-893 (1997)

On the character of the orbital period changes in the interacting binary RW Tauri

V. imon

Astronomical Institute, Academy of Sciences, 251 65 Ondejov, Czech Republic

Received 3 April 1996 / Accepted 27 August 1996

Abstract

An analysis of the minima timings covering more than a century showed that two seasons of activity can be established (JD = 2 410 000 - 2 423 000 and JD = 2 435 000 - 2 450 000), separated by an interval about 12 000 days (33 years) long in which the period was almost invariable. Most period variations in each season have character of episodes of abrupt changes of both signs and are separated by intervals of almost constant period. The length of interval separating the episodes is more than a thousand days. The net result of the respective episodes was shortening of the orbital period. The episodes of the period decrease in 1982 and 1987 coincide with the minimum brightness of the loser (photometry of Olson and Etzel 1993). It is concluded that variations of the orbital period in RW Tau are not evolutionary and probably are not directly related to the mass transfer events. Instead, an alternative interpretation incorporating changes of the internal structure of the convective loser is offered.

Key words: stars: activity  binaries: close  binaries: eclipsing  circumstellar matter  stars: interiors  stars: individual: RW Tau

Send offprint requests to: V. imon (simon@sunstel.asu.cas.cz)

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Contents

• 1. Introduction
• 2. Collection of the data
• 3. Influence of the eclipse light curve changes
• 4. Analysis of the data
  • 4.1. Analysis of Season II
  • 4.2. Analysis of Season I
  • 4.3. Comparison with U Cep
  • 4.4. Relation of the and brightness changes
  • 4.5. Relation of the changes and the mass transfer events
• 5. Discussion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: July 3, 1998
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