UBV photometry and period variations of V 839 Ophiuchi ^*

Ankara University Observatory, Science Faculty, Tandogan 06100, Ankara, Turkey

Received: 2 January 1996
Accepted: 20 January 1997

Abstract

A complete period variation analysis and new light curves of V 839 Oph together with new ephemeris data are presented. The period variation was found to be . The period increment indicates that the conservative mass transfer rate from the less massive component to the more massive one is . We fitted parabolic and we discuss the possible detection of sinusoidal curves to the () diagram and sinusoidal oscillations with period of about and semi-amplitude of 0.0065 day. A simultaneous solution of the B and V light curves was computed using the Wilson-Devinney synthetic light-curve code. The light curve solution indicates that the A-type W UMa-type system is in contact with a filling factor of .