ORBITAL PERIOD VARIATIONS IN V4140 SGR (NSV 12615)

We present 20 new eclipse timings for V4140 Sgr (NSV 12615). The analysis of this data together with 25 timings obtained earlier by Baptista et al. ( 1989, MNRAS, 241, 63 1 ) indicates that the orbital period is not constant. The inclusion of a nonlinear term in the ephemeris to predict the times of minimum is significant at a 3-sigma level, either considering a quadratic or a sinusoidal behavior versus time. If the quadratic fit is the correct one, the system is increasing its orbital period in a time scale of 1.2 X 10(7) years, with a mass transfer rate of M2 congruent-to 10(-9) M. yr-1. The corresponding orbital period derivative (P) is very similar to the one earlier determined for Z Cha (Wood et al. 1986, MNRAS, 219, 629). If the sinusoidal fit is correct, the system presents a cycle of 5.4 years, which may be explained in terms of a magnetic activity cycle in the secondary star. The observed orbital period variations can ot be explained as a result of either apsidal motion or orbital motion around a third body.