Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VI: The Sixth Year (2013-2014)
Continuing the project described by Kato et al. (2009, PASJ, 61, S395, arXiv:0905.1757), we collected times of superhump maxima for 56 SU UMa-type dwarf novae mainly observed during the 2013-2014 season and characterized these objects. We detected negative superhumps in VW Hyi and indicated that the low number of normal outbursts in some supercycle can be interpreted as a result of the disk tilt. This finding, combined with the Kepler observation of V1504 Cyg and V344 Lyr, suggests that the disk tilt is responsible for modulating the outburst pattern in SU UMa-type dwarf novae. We also studied the deeply eclipsing WZ Sge-type dwarf nova MASTER OT J005740.99+443101.5 and found evidence of a sharp eclipse during the phase of early superhumps. The profile can be reproduced by a combination of the eclipse of the axisymmetric disk and the uneclipsed light source of early superhumps. This finding confirms the lack of evince of a greatly enhanced hot spot during the early stage of WZ Sge-type outburst. We detected growing (stage A) superhumps in MN Dra and give a suggestion that some of SU UMa-type dwarf novae situated near the critical condition of tidal instability may show long-lasting stage A superhumps. The large negative period derivatives reported in such systems can be understood a result of the combination of stage A and B superhumps. The WZ Sge-type dwarf novae AL Com and ASASSN-13ck showed a long-lasting (plateau-type) rebrightening. In the early phase of the rebrightening, both objects showed a precursor-like outburst, suggesting that the long-lasting rebrightening is triggered by a precursor outburst.
Authors: Taichi Kato (Kyoto U), Pavol A. Dubovsky, Igor Kudzej, Franz-Josef Hambsch, Ian Miller, Tomohito Ohshima, Chikako Nakata, Miho Kawabata, Hirochika Nishino, Kazunari Masumoto, Sahori Mizoguchi, Masayuki Yamanaka, Katsura Matsumoto, Daisuke Sakai, Daiki Fukushima, Minami Matsuura, Genki Bouno, Megumi Takenaka, Shinichi Nakagawa, Ryo Noguchi, Eriko Iino, Roger D. Pickard, Yutaka Maeda, Arne Henden, Kiyoshi Kasai, Seiichiro Kiyota, Hidehiko Akazawa, Kazuyoshi Imamura, Enrique de Miguel, Hiroyuki Maehara, Berto Monard, Elena P. Pavlenko, Kirill Antonyuk, Nikolaj Pit, Oksana I. Antonyuk, Aleksei V. Baklanov, Javier Ruiz, Michael Richmond, Arto Oksanen, Caisey Harlingten, Sergey Yu. Shugarov, Drahomir Chochol, Gianluca Masi, Francesca Nocentini, Patrick Schmeer, Greg Bolt, Peter Nelson, Joseph Ulowetz, Richard Sabo, William N. Goff, William Stein, Raul Michel, Shawn Dvorak, Irina B. Voloshina, Vladimir Metlov, Natalia Katysheva, Vitaly V. Neustroev, George Sjoberg, Colin Littlefield, Bartlomiej Debski, Paulina Sowicka, Marcin Klimaszewski, Malgorzata Curylo, Etienne Morelle, Ivan A. Curtis, Hidetoshi Iwamatsu, Neil D. Butterworth, Maksim V. Andreev, Nikolai Parakhin, Aleksandr Sklyanov, Kazuhiko Shiokawa, Rudolf Novak, Tat'yana R. Irsmambetova, Hiroshi Itoh, Yoshiharu Ito, Kenji Hirosawa, Denis Denisenko, Christopher S. Kochanek, Benjamin Shappee, Krzysztof Z. Stanek, Jose L. Prieto, Koh-ichi Itagaki, Rod Stubbings, Jose Ripero, Eddy Muyllaert, Gary Poyner