Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. V: The Fifth Year (2012-2013)
Creators: name: Kato, Taichi
name: Hambsch, Franz-Josef
name: Maehara, Hiroyuki
name: Masi, Gianluca
name: Nocentini, Francesca
name: Dubovsky, Pavol A.
name: Kudzej, Igor
name: Imamura, Kazuyoshi
name: Ogi, Minako
name: Tanabe, Kenji
name: Akazawa, Hidehiko
name: Krajci, Thomas
name: Miller, Ian
name: de Miguel, Enrique
name: Henden, Arne
name: Littlefield, Colin
name: Noguchi, Ryo
name: Ishibashi, Takehiro
name: Ono, Rikako
name: Kawabata, Miho
name: Kobayashi, Hiroshi
name: Sakai, Daisuke
name: Nishino, Hirochika
name: Furukawa, Hisami
name: Masumoto, Kazunari
name: Matsumoto, Katsura
name: Ohshima, Tomohito
name: Nakata, Chikako
name: Honda, Satoshi
name: Kinugasa, Kenzo
name: Hashimoto, Osamu
name: Stein, William
name: Pickard, Roger D.
name: Kiyota, Seiichiro
name: Pavlenko, Elena P.
name: Antonyuk, Oksana I.
name: Baklanov, Aleksei V.
name: Antonyuk, Kirill
name: Samsonov, Denis
name: Pit, Nikolaj
name: Sosnovskij, Aleksei
name: Oksanen, Arto
name: Harlingten, Caisey
name: Tyyska, Jenni
name: Monard, Berto
name: Shugarov, Sergey Yu.
name: Chochol, Drahomir
name: Kasai, Kiyoshi
name: Maeda, Yutaka
name: Hirosawa, Kenji
name: Itoh, Hiroshi
name: Sabo, Richard
name: Ulowetz, Joseph
name: Morelle, Etienne
name: Michel, Raul
name: Suarez, Genaro
name: James, Nick
name: Dvorak, Shawn
name: Voloshina, Irina B.
name: Richmond, Michael
name: Staels, Bart
name: Boyd, David
name: Andreev, Maksim V.
name: Parakhin, Nikolai
name: Katysheva, Natalia
name: Miyashita, Atsushi
name: Nakajima, Kazuhiro
name: Bolt, Greg
name: Padovan, Stefano
name: Nelson, Peter
name: Starkey, Donn R.
name: Buczynski, Denis
name: Starr, Peter
name: Goff, William N.
name: Denisenko, Denis
name: Kochanek, Christopher S.
name: Shappee, Benjamin
name: Stanek, Krzysztof Z.
name: Prieto, Jose L.
name: Itagaki, Koh-ichi
name: Kaneko, Shizuo
name: Stubbings, Rod
name: Muyllaert, Eddy
name: Shears, Jeremy
name: Schmeer, Patrick
name: Poyner, Gary
name: Marco, Miguel Rodriguez
Publisher: name: arXiv
Year: 2013
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Continuing the project described by Kato et al. (2009a, arXiv:0905.1757), we collected times of superhump maxima for SU UMa-type dwarf novae mainly observed during the 2012-2013 season. We found three objects (V444 Peg, CSS J203937 and MASTER J212624) having strongly positive period derivatives despite the long orbital period (Porb). By using the period of growing stage (stage A) superhumps, we obtained mass ratios for six objects. We characterized nine new WZ Sge-type dwarf novae. We made a pilot survey of the decline rate of slowly fading part of SU UMa-type and WZ Sge-type outbursts. The decline time scale was found to generally follow the expected Porb^(1/4) dependence and WZ Sge-type outbursts also generally follow this trend. There are some objects which show slower decline rates, and we consider these objects good candidates for period bouncers. We also studied unusual behavior in some objects, including BK Lyn which made a transition from an ER UMa-type state to the novalike (standstill) state in 2013 and unusually frequent occurrence of superoutbursts in NY Ser and CR Boo. We applied least absolute shrinkage and selection operator (Lasso) power spectral analysis, which has been proven to be very effective in analyzing the Kepler data, to ground-based photometry of BK Lyn and detected the dramatic disappearance of the signal of negative superhumps in 2013. We suggested that the mass-transfer rates did not vary strongly between the ER UMa-type state and novalike state in BK Lyn, and this transition was less likely caused by a systematic variation of the mass-transfer rate.
description: 83 pages, 95 figures, accepted for publication in PASJ