Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. II The Second Year (2009–2010)
Year: 2010
Type: article
Abstract: Continued from Kato et al. (2009, PASJ, 61, S395), we collected the times of superhump maxima for 68 SU UMa-type dwarf novae, mainly observed during the 2009–2010 season. The newly obtained data confirmed the basic findings reported in Kato et al. (ibid.): the presence of stages A–C and the predominance of positive period derivatives during stage B in systems with superhump periods shorter than 0.07 d. There was a systematic difference in the period derivatives for the systems with superhump periods longer than 0.075 d between this study and Kato et al. (ibid.). We suggest that this difference was possibly caused by a relative lack of frequently outbursting SU UMa-type dwarf novae in this period regime in the present study. We recorded a strong beat phenomenon during the 2009 superoutburst of IY UMa. A close correlation between the beat period and the superhump period suggests that the changing angular velocity of the apsidal motion of the elliptical disk is responsible for the variation of the superhump periods. We also described three new WZ Sge-type objects with established early superhumps and one with likely early superhumps. We suggest that two systems, VX For and EL UMa, are WZ Sge-type dwarf novae with multiple rebrightenings. The $O-C$ variation in OT J213806.6$+$261957 suggests that the frequent absence of rebrightenings in very short-$P_{\rm orb}$ objects can be the result of a sustained superoutburst plateau at the epoch when usual SU UMa-type dwarf novae return to quiescence, preceding a rebrightening. We also present a formulation for a variety of Bayesian extensions to traditional period analyses.
Authors: Taichi Kato, Hiroyuki Maehara, Makoto Uemura, Arne Henden, Enrique De Miguel, Ian Miller, Pavol A. Dubovsky, Igor Kudzej, Seiichiro Kiyota, Franz-Josef Hambsch, Kenji Tanabe, Kazuyoshi Imamura, Nanae Kunitomi, Ryosuke Takagi, Mikiha Nose, Hidehiko Akazawa, Gianluca Masi, Shinichi Nakagawa, Eriko Iino, Ryo Noguchi, Katsura Matsumoto, Daichi Fujii, Hiroshi Kobayashi, Kazuyuki Ogura, Sachi Ohtomo, Kousei Yamashita, Hirofumi Yanagisawa, Hiroshi Itoh, Greg Bolt, Berto Monard, Tomohito Ohshima, Jeremy Shears, Javier Ruiz, Akira Imada, Arto Oksanen, Peter Nelson, Tomas L. Gomez, Bart Staels, David Boyd, Irina B. Voloshina, Thomas Krajci, Tim Crawford, Chris Stockdale, Michael Richmond, Etienne Morelle, Rudolf NovÁk, Daisaku Nogami, Ryoko Ishioka, Steve Brady, Mike Simonsen, Elena P. Pavlenko, Frederick A. Ringwald, Tetsuya Kuramoto, Atsushi Miyashita, Roger D. Pickard, Tomáš Hynek, Shawn Dvorak, Rod Stubbings, Eddy Muyllaert
Institutions: Kyoto University, Hiroshima University, American Association of Variable Star Observers, Universidad de Huelva, Vihorlat Observatory, Variable Star Observers League in Japan, Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne, Okayama University of Science, Osaka Kyoiku University, Bronberg Observatory, Instituto de Física de Cantabria, National Astronomical Observatory of Japan, Universidad Complutense de Madrid, Consejo Superior de Investigaciones Científicas, Institute of Mathematical Sciences, Universidad Carlos III de Madrid, Universidad Autónoma de Madrid, British Astronomical Association, Lomonosov Moscow State University, Rochester Institute of Technology, Brno University of Technology, Crimean Astrophysical Observatory, California State University, Fresno, VSB - Technical University of Ostrava, Rolling Hills Observatory, Tetoora Road Observatory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2596480648