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arXiv · 0912.4321

Dwarf Novae in the Shortest Orbital Period Regime: I. A New Short Period Dwarf Nova, OT J055717+683226

Makoto Uemura·Akira Arai·Taichi Kato·Hiroyuki Maehara·Daisaku Nogami·Kaori Kubota·Yuuki Moritani·Akira Imada·Toshihiro Omodaka·Shota Oizumi·Takashi Ohsugi·Takuya Yamashita·Koji S. Kawabata·Mizuki Isogai·Osamu Nagae·Mahito Sasada·Hisashi Miyamoto·Takeshi Uehara·Hiroyuki Tanaka·Risako Matsui·Yasushi Fukazawa·Shuji Sato·Masaru Kino
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Abstract

We report the observation of a new dwarf nova, OT J055717+683226, during its first-ever recorded superoutburst in December 2006. Our observation shows that this object is an SU UMa-type dwarf nova having a very short superhump period of 76.67+/- 0.03 min (0.05324+/-0.00002 d). The next superoutburst was observed in March 2008. The recurrence time of superoutbursts (supercycle) is, hence, estimated to be ~480 d. The supercycle is much shorter than those of WZ Sge-type dwarf novae having supercycles of >~ 10 yr, which are a major population of dwarf novae in the shortest orbital period regime (<~85 min). Using a hierarchical cluster analysis, we identified seven groups of dwarf novae in the shortest orbital period regime. We identified a small group of objects that have short supercycles, small outburst amplitudes, and large superhump period excesses, compared with those of WZ Sge stars. OT J055717+683226 probably belongs to this group.

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Makoto Uemura, Akira Arai, Taichi Kato, Hiroyuki Maehara, Daisaku Nogami, Kaori Kubota, Yuuki Moritani, Akira Imada, Toshihiro Omodaka, Shota Oizumi, Takashi Ohsugi, Takuya Yamashita, Koji S. Kawabata, Mizuki Isogai, Osamu Nagae, Mahito Sasada, Hisashi Miyamoto, Takeshi Uehara, Hiroyuki Tanaka, Risako Matsui, Yasushi Fukazawa, Shuji Sato, Masaru Kino. 2009-12-22. Dwarf Novae in the Shortest Orbital Period Regime: I. A New Short Period Dwarf Nova, OT J055717+683226. https://doi.org/10.1093/pasj%2F62.1.187

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