NEW ECLIPSE TIMINGS AND AN UPPER LIMIT TO THE RATE OF MASS-TRANSFER IN THE NOVA-LIKE VARIABLE RW TRI

We have measured new times of minima for the eclipses of the novalike cataclysmic variable RW Tri. We use the timings to revise the eclipse ephemeris and to place a limit on the rate of change of the orbital period. The revised ephemeris is T(min) = JD. 2 441 129.36487 + 0.231883297E, and the upper limit to the rate of change of the orbital period is \P\ < 5.6 x 10(-12). From the limit on P, we derive an upper limit of \M\ < 5.6 x 10(-9) M. yr-1 on the rate of mass transfer in the system. This limit is a factor of 2 less than the rates of mass transfer predicted by several recent calculations of the evolution of cataclysmic variables. The limit is consistent with models of dwarf nova eruptions.