Publication details

Period study of TW Draconis


ZEJDA Miloslav MIKULÁŠEK Zdeněk WOLF Marek

Year of publication 2008
Type Article in Periodical
Magazine / Source Astronomy and Astrophysics
MU Faculty or unit

Faculty of Science

Field Astronomy and astrophysics
Keywords stars: binaries: eclipsing; stars: individual: TW Dra; stars: fundamental parameters
Description TW Draconis is one of the most well known interacting Algol-type eclipsing binaries. We study time series data for the star accumulated over the past 150 years to detect changes in minima timings. Using 561 available minima timings, we compile an extended O-C diagram analysis. The first part ending around 1942 is characterised by smooth linear/parabolic course of timing residuals. In 1858-1905, the period was almost constant P=2.806513(9)d, but, in 1905-1942, the period increased. We interpret it as a result of continuous mass exchange at the mean rate of 6.9x10^-7 Ms year-1. Since 1942, the system has been showing alternating and shortening period changes with the length of a cycle of about two decades, modulated by short-term periodic variations. The latter small variations with the period 6.5 years are caused by the the presence of a third low-mass body in the system. Major oscillations can be explained as consequences of quadrupole moment variation in the system.
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