OUTBURST-RELATED PERIOD CHANGES OF RECURRENT NOVA CI AQUILAE

Pre-outburst and post-outburst light curves and post-outburst eclipse timings are analyzed to measure any period (P) change related to nova CI Aql's outburst of early 2000 and a mean post-outburst dP/dt, which then lead to estimates of the accreting component's rate of mass (M) change and its overall outburst-related change of mass over roughly a decade of observations. We apply a recently developed procedure for unified analysis of three timing-related data types (light curves, radial velocities, and eclipse timings), although with only light curves and timings in this case. Fits to the data are reasonably good without need for a disk in the light-curve model, although the disk certainly exists and has an important role in our post-outburst mass flow computations. Initial experiments showed that, although there seems to be an accretion hot spot, it has essentially no effect on derived outburst-related Delta P or on post-outburst dP/dt. Use of atomic time (HJED) in place of HJD also has essentially nil effect on Delta P and dP/dt. We find Delta P consistently negative in various types of solutions, although at best only marginally significant statistically in any one experiment. Pre-outburst HJD(0) and P results are given, as are post-outburst HJD(0), P, and dP/dt, with light curves and eclipse times as joint input, and also with only eclipse time input. Post-outburst dP/dt is negative at about 2.4 sigma. Explicit formulae for mass transfer rates and epoch-to-epoch mass change are developed and applied. A known offset in the magnitude zero point for 1991-1994 is corrected.