A cyclical period variation detected in the updated orbital period analysis of TV Columbae

摘要

The two CCD photometries of the intermediate polar TV Columbae are made forobtaining the two updated eclipse timings with high precision. There is aninterval time \sim 17yr since the last mid-eclipse time observed in 1991. Thus,the new mid-eclipse times can offer an opportunity to check the previousorbital ephemerides. A calculation indicates that the orbital ephemeris derivedby Augusteijn et al. (1994) should be corrected. Based on the proper linearephemeris (Hellier, 1993), the new orbital period analysis suggests a cyclicalperiod variation in the O-C diagram of TV Columbae. Using Applegate's mechanismto explain the periodic oscillation in O-C diagram, the required energy islarger than that a M0-type star can afford over a complete variation period\sim 31.0(\pm 3.0)yr. Thus, the light travel-time effect indicates that thetertiary component in TV Columbae may be a dwarf with a low mass, which is nearthe mass lower limit \sim 0.08Msun as long as the inclination of the third bodyhigh enough.