ON THE M-V(PEAK) VERSUS ORBITAL PERIOD RELATION FOR DWARF NOVA OUTBURSTS

We present computations for the accretion disk limit cycle model in an attempt to explain the empirical relation for dwarf nova outbursts be tween the peak visual absolute magnitude and orbital period found by W arner. For longer period systems one sees intrinsically brighter outbu rsts. This is accounted for in the limit cycle model by the scaling wi th radius of the critical surface density Sigma(max) that triggers the dwarf nova outbursts. During the storage phase of the instability, th e accretion disk mass must be less than some maximum value, a value th at scales with radius and therefore with orbital period. When the inst ability is triggered and the accumulated mass is redistributed into a quasi-steady state disk in outburst, the resultant peak optical flux f rom the disk is a measure of the total mass that was stored in quiesce nce. We compute light curves for a range in outer disk radius (or equi valently, orbital period), and find that our peak values of M-V are wi thin less than 1 mag of the observed relation M-V(peak) = 5.64 - 0.259 P(orbital) for 2 less than or similar to P-orbital less than or simila r to 8, where P-orbital is in hours.