In 2015 March , the notable WZ Sge-type dwarf nova AL Com exhibited an unusual outburst with a recurrence time of { \sim } 1.5 yr , which is the shortest interval of superoutbursts among WZ Sge-type dwarf novae .
Early superhumps in the superoutburst light curve were absent , and a precursor was observed at the onset of the superoutburst for the first time in WZ Sge-type dwarf novae .
The present superoutburst can be interpreted as a result of the condition that the disk radius barely reached the 3:1 resonance radius , but did not reach the 2:1 resonance one .
Ordinary superhumps immediately grew following the precursor .
The initial part of the outburst is indistinguishable from those of superoutbursts of ordinary SU UMa-type dwarf novae .
This observation supports the interpretation that the 2:1 resonance suppresses a growth of ordinary superhumps .
The estimated superhump period and superhump period derivative are P _ { sh } = 0.0573185 ( 11 ) d and P _ { dot } = +1.5 ( 3.1 ) \times 10 ^ { -5 } , respectively .
These values indicate that the evolution of ordinary superhumps is the same as \textcolor blackthat in past superoutbursts with much larger extent .
Although the light curve during the plateau stage was typical for an SU UMa-type dwarf nova , this superoutburst showed a rebrightening , together with a regrowth of the superhumps .
The overall light curve of the rebrightening was the almost the same as those observed in previous rebrightenings .
This implies that the rebrightening type is inherent in the system .