A growth of early superhump: Multi color observation of the WZ Sge star TCP J23580961+5502508

TL;DR

This study presents multi-color optical and near-infrared observations of the 2022 superoutburst of the WZ Sge-type dwarf nova TCP J23580961+5502508, revealing evolving accretion disk structures during early superhumps.

Contribution

First multi-color observation of early superhumps in this dwarf nova, reconstructing disk structure and revealing dynamic flaring patterns during outburst.

Findings

Detected early superhumps with changing profiles over three days.

Reconstructed accretion disk shows evolving flaring structures.

Identified a two-armed pattern consistent with the 2:1 resonance model.

Abstract

We report optical and near-infrared photometry of a WZ Sge-type dwarf nova, TCP J23580961+5502508, during its 2022 superoutburst, obtained using the 1.5-m Kanata telescope. Our observation detected early superhumps on three consecutive nights which included the rising phase toward the peak of the outburst. The early superhumps exhibited a profile dominated by the primary maximum during the first two days, while a prominent secondary minimum appeared on the third day. We reconstructed the structure of the accretion disk from multi-color light curves using the early superhump mapping. The accretion disk has a prominent flaring structure on the leading side of the disk during the first two days. An additional flaring structure emerged on the opposite side on the third day, forming a two-armed pattern that can be interpreted within the framework of the 2:1 resonance model. The reconstructed disk structure in the first two days suggests the presence of an additional mechanism operating during the initial stage of early superhump development.