@article{3017135,
    title = "Survey of period variations of superhumps in su UMa-type dwarf novae",
    author = "Kato, T. and Imada, A. and Uemura, M. and Nogami, D. and Maehara, H. and Ishioka, R. and Baba, H. and Matsumoto, K. and Iwamatsu, H. and Kubota, K. and Sugiyasu, K. and Soejima, Y. and Moritani, Y. and Ohshima, T. and Ohashi, H. and Tanaka, J. and Sasada, M. and Arai, A. and Nakajima, K. and Kiyota, S. and Tanabe, K. and Imamura, K. and Kunitomi, N. and Kunihiro, K. and Taguchi, H. and Koizumi, M. and Yamada, N. and Nishi, Y. and Kida, M. and Tanaka, S. and Ueoka, R. and Yasui, H. and Maruoka, K. and Henden, A. and Oksanen, A. and Moilanen, M. and Tikkanen, P. and Mika, A.H.O. and Monard, B. and Itoh, H. and Dubovsky, P.A. and Kudzej, I. and Dancikova, R. and Vanmunster, T. and Pietz, J. and Bolt, G. and Boyd, D. and Nelson, P. and Krajci, T. and Cook, L.M. and Torii, K. and Starkey, D.R. and Shears, J. and Jensen, L.-T. and Masi, G. and Hynek, T. and Novák, R. and Kocián, R. and Král, L. and Kučáková, H. and Kolasa, M. and Šťastný, P. and Staels, B. and Miller, I. and Sano, Y. and Ponthière, P.D.E. and Miyashita, A. and Crawford, T. and Brady, S. and Santallo, R. and Richards, T. and Martin, B. and Buczynski, D. and Richmond, M. and Kern, J. and Davis, S. and Crabtree, D. and Beaulieu, K. and Davis, T. and Aggleton, M. and Morelle, E. and Pavlenko, E.P. and Andreev, M. and Baklanov, A. and Koppelman, M.D. and Billings, G. and Urbančok, L. and Ögmen, Y. and Heathcote, B. and Gomez, T.L. and Voloshina, I. and Retter, A. and Mularczyk, K. and Złoczewski, K. and Olech, A. and Kedzierski, P. and Pickard, R.D. and Stockdale, C. and Virtanen, J. and Morikawa, K. and Hambsch, F.-J. and Garradd, G. and Gualdoni, C. and Geary, K. and Omodaka, T. and Sakai, N. and Michel, R. and Cárdenas, A.A. and Gazeas, K.D. and Niarchos, P.G. and Yushchenko, A.V. and Mallia, F. and Fiaschi, M. and Good, G.A. and Walker, S. and James, N. and Douzu, K.-I. and Julian II, W.M. and Butterworth, N.D. and Shugarov, S.Yu. and Volkov, I. and Chochol, D. and Katysheva, N. and Rosenbush, A.E. and Khramtsova, M. and Kehusmaa, P. and Reszelski, M. and Bedient, J. and Liller, W. and Pojmański, G. and Simonsen, M. and Stubbings, R. and Schmeer, P. and Muyllaert, E. and Kinnunen, T. and Poyner, G. and Ripero, J. and Kriebel, W.",
    journal = "Publications of the Astronomical Society of Japan",
    year = "2009",
    volume = "61",
    number = "SPEC. ISS. 2",
    pages = "S395-S616",
    publisher = "Oxford University Press",
    issn = "0004-6264, 2053-051X",
    doi = "10.1093/pasj/61.sp2.s395",
    keywords = "Surveys;  Stars, Accretion: accretion disks;  Cataclysmic variables;  Dwarf novae;  Evolutionary stage;  Late stage;  Long lasting;  Mass ratio;  Orbital periods;  Stars: dwarf novae;  Stars: novae: cataclysmic variables, Stars;  Surveys",
    abstract = "We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of the superhump period is found to be composed of three distinct stages: an early evolutionary stage with a longer superhump period, a middle stage with systematically varying periods, and a final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods of less than 0.08 d show positive period derivatives. We present observational characteristics of these stages and give greatly improved statistics. Contrary to an earlier claim, we found no clear evidence for a variation of period derivatives among different superoutbursts of the same object. We present an interpretation that the lengthening of the superhump period is a result of the outward propagation of an eccentricity wave, which is limited by the radius near the tidal truncation. We interpret that late-stage superhumps are rejuvenated excitation of a 3:1 resonance when superhumps in the outer disk are effectively quenched. The general behavior of the period variation, particularly in systems with short orbital periods, appears to follow a scenario proposed in Kato, Maehara, and Monard (2008, PASJ, 60, L23). We also present an observational summary of WZ Sge-type dwarf novae. Many of them have shown long-enduring superhumps during a post-superoutburst stage having longer periods than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently with the mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives, and are excellent candidates for those systems around or after the period minimum of evolution of cataclysmic variables. © 2009. Astronomical Society of Japan."
}