SSS J122221.7-311523: Double Superoutburst in a Best Candidate Period Bouncer

TL;DR

This paper reports on the observation of a unique double superoutburst in the transient SSS J122221.7-311523, revealing a very low mass ratio and suggesting it as a prime candidate for a period bouncer in cataclysmic variables.

Contribution

It provides the first detailed analysis of a double superoutburst in this object, linking the pattern to a low mass ratio and period bouncer status, which is novel in the study of hydrogen-rich CVs.

Findings

Detected successive superoutbursts with growing superhumps.

Estimated a very small mass ratio q < 0.05.

Identified the object as a potential period bouncer.

Abstract

We observed the 2012-2013 superoutburst of the newly identified transient SSS J122221.7-311523 and found that this object showed successive two superoutbursts. Superhumps grew in amplitude during the second superoutburst and showed a characteristic pattern of period change reflecting the growth of the superhump. Assuming that the periods of superhumps during the growing stage [0.07721(1) d] and post-superoutburst stage [0.07673(3) d], represent the dynamical precession rates at the radius of the 3:1 resonance and the radius immediately after the superoutburst, respectively, we found that this object has a very small mass ratio q=M2/M1 < 0.05. The possible orbital period from quiescent data suggests q=0.045, one of the smallest among hydrogen-rich cataclysmic variables. The long orbital period and low q make this object a perfect candidate for a period bouncer. We suggest that the peculiar pattern of double superoutburst is a result of a low q and may be characteristic to period bouncers.