Superhumps and post-outburst rebrightening episodes in the AM CVn star SDSS J012940.05+384210.4

Understand

We report unfiltered photometry of the first confirmed outburst of the AM CVn system SDSS J012940.05+384210.4 during 2009 December.

• At its brightest the star was magnitude 14.5, 5.4 magnitudes above mean quiescence.
• Although the first part of the outburst was not observed, six remarkable rebrightening events were observed during the course of the outburst.
• Forty-one days after the outburst was detected, the star was still 1.7 magnitudes above quiescence.