2003AJ....125.2188K

About 10.5 yr of V-band photometry of QQ Vul allows the examination of systematic changes in orbital light curve features of the system. The photometry is generally limited to one or two data points each clear night at a random orbital phase; however, the orbital light curve and its slower changes can be studied when the data are grouped into intervals of 1 to 2 months. We have isolated four main distinguishing behaviors in the optical light curve of the system. In type 1 the phased light curve has a single broad primary dip. In type 2 the primary dip retains its shape but becomes dimmer and is accompanied by a secondary dip about 0.5 phase units away. As part of the type 2 behavior there is a decrease in the overall brightness level of the phased light curve by ∼0.5 mag. This correlation between the morphology of the orbital light curve and the brightness of the system is shown to hold not only for our new data but also for light curves obtained during 1982-1986. Type 3 behavior is an unresolved mixture of types 1 and 2, whereas type 4 appears to be an extreme bright case of type 1. We find a highly significant correlation between the depth of the secondary dip and the system brightness. The implications of this correlation in the context of one- or two-pole accretion are discussed.