SDSS J080434.20+510349.2: Eclipsing WZ Sge-Type Dwarf Nova with Multiple Rebrightenings

TL;DR

This study presents detailed observations of the 2006 superoutburst of SDSS J080434.20+510349.2, revealing its eclipsing nature, superhump behavior, and rebrightening phenomena, offering insights into the mechanisms of rebrightenings in WZ Sge-type dwarf novae.

Contribution

First detailed analysis of SDSS J080434.20+510349.2's superoutburst, showing its eclipsing nature, superhump evolution, and rebrightening behavior, advancing understanding of WZ Sge-type dwarf novae.

Findings

SDSS J080434.20+510349.2 is a grazing eclipsing system with a 0.0590048-day period.

Superhump periods varied, with longer periods during rebrightening and post-superoutburst phases.

Superhumps during mini-outbursts suggest transient excitation related to rebrightening mechanisms.

Abstract

We observed the 2006 superoutburst of SDSS J080434.20+510349.2 during its plateau phase, rebrightening phase, and post-superoutburst final decline. We found that this object is a grazing eclipsing system with a period of 0.0590048(2) d. Well-defined eclipses were only observed during the late stage of the superoutburst plateau and the depth decreased during the subsequent stages. We determined the superhump period during the superoutburst plateau to be 0.059539(11) d, giving a fractional superhump excess of 0.90(2)%. During the rebrightening and post-superoutburst phases, persisting superhumps with periods longer than those of superhumps during the plateau phase: 0.059632(6) during the rebrightening phase and 0.05969(4) d during the final fading. This phenomenon is very well in line with the previously known long-period "late superhumps" in GW Lib, V455 And and WZ Sge. The amplitudes of orbital humps between different states of rebrightenings suggest that these humps do not arise from the classical hot spot, but are more likely a result of projection effect in a high-inclination system. There was no clear evidence for the enhanced hot spot during the rebrightening phase. We also studied previously reported "mini-outbursts" in the quiescent state and found evidence that superhumps were transiently excited during these mini-outbursts. The presence of grazing eclipses and distinct multiple rebrightenings in SDSS J080434.20+510349.2 would provide a unique opportunity to understanding the mechanism of rebrightenings in WZ Sge-type dwarf novae.