Survey of period variations of superhumps in SU UMa-type dwarf novae. VI. The sixth year (2013–2014)
Authors: Kato Taichi , Dubovsky Pavol A. , Kudzej Igor , Hambsch Franz-Josef , Miller Ian , Ohshima Tomohito , Nakata Chikako , Kawabata Miho , Nishino Hirochika , Masumoto Kazunari , Mizoguchi Sahori , Yamanaka Masayuki , Matsumoto Katsura , Sakai Daisuke , Fukushima Daiki , Matsuura Minami , Bouno Genki , Takenaka Megumi , Nakagawa Shinichi , Noguchi Ryo , Iino Eriko , Pickard Roger D. , Maeda Yutaka , Henden Arne , Kasai Kiyoshi , Kiyota Seiichiro , Akazawa Hidehiko , Imamura Kazuyoshi , de Miguel Enrique , Maehara Hiroyuki , Monard Berto , Pavlenko Elena P. , Antonyuk Kirill , Pit Nikolaj , Antonyuk Oksana I. , Baklanov Aleksei V. , Ruiz Javier , Richmond Michael , Oksanen Arto , Harlingten Caisey , Shugarov Sergey Yu. , Chochol Drahomir , Masi Gianluca , Nocentini Francesca , Schmeer Patrick , Bolt Greg , Nelson Peter , Ulowetz Joseph , Sabo Richard , Goff William N. , Stein William , Michel Raúl , Dvorak Shawn , Voloshina Irina B. , Metlov Vladimir , Katysheva Natalia , Neustroev Vitaly V. , Sjoberg George , Littlefield Colin , Dębski Bartłomiej , Sowicka Paulina , Klimaszewski Marcin , Curyło Małgorzata , Morelle Etienne , Curtis Ivan A. , Iwamatsu Hidetoshi , Butterworth Neil D. , Andreev Maksim V. , Parakhin Nikolai , Sklyanov Aleksandr , Shiokawa Kazuhiko , Novák Rudolf , Irsmambetova Tat'yana R. , Itoh Hiroshi , Ito Yoshiharu , Hirosawa Kenji , Denisenko Denis , Kochanek Christopher S. , Shappee Benjamin , Stanek Krzysztof Z. , Prieto José L. , Itagaki Koh-ichi , Stubbings Rod , Ripero Jose , Muyllaert Eddy , Poyner Gary 
Published: November 2014

Continuing the project undertaken by Kato et al. (2009), 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 supercycles can be interpreted as a result of disk tilt. This finding, combined with the Kepler observation of V1504 Cyg and V344 Lyr, suggests that 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 shows the lack of evidence for 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 as a result of the combination of stage A and B superhumps. Two WZ Sge-type dwarf novae, AL Com and ASASSN-13ck, showed a long-lasting (plateau-type) rebrightening. In the early phase of their rebrightenings, both objects showed a precursor-like outburst, suggesting that the long-lasting rebrightening is triggered by a precursor outburst.