The results questioned our understanding of Z Cam stars. It is the prototype star of a subclass of dwarf nova-type cataclysmic variables. The Z Camelopardalis stars are especially known for their random standstills .
Plateau outbursts are brighter and last longer than common outbursts.
Some outbursts end in standstills in which the brightness stays constant roughly 1 mag below maximum light for a few days to 1,000 days. The average energy output in a standstill is larger than that during an outburst cycle. All outbursts follow a pattern, the plateau outburst cycle , in which one or more common or anomalous outbursts occur between two plateau outbursts or a plateau outburst and a standstill. Short quiescent durations lead to a higher outburst frequency and more energetic outbursts in intervals dominated by standstills than in other lightcurve intervals. Our physical picture for Z Camelopardalis stars follows the standard disk instability mechanism for dwarf novae.