The optical light curve of Nova Herculis 1991 and of other classical novae

Observations of an eclipse in the light curve (LC) of the classical Nova Herculis 1991, following its outburst in 1991 March, enable us to decompose the LC into two distinct curves, one of the white dwarf (WD) and one of an accretion disk in this stellar system. It is shown that during the first 50 days after maximum light, the visual LC of the system was dominated by the light of the WD, and that from this time on, the LC is that of the disk. There are two independent observations that support this notion. We suggest that a similar distinction can be recognized in the LC of other classical novae. We also suggest that the oscillations marking the "transition stage" in the declining LC of novae are accretion disk phenomena, akin to the processes in the disks of dwarf novae that give rise to the outbursts of these objects.