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Our research on variable objects based on the VSNET collaborations has achieved much progress in understanding the nature of many kinds of phenomena. Many problems have appeared, instead. Among them, we here review three newly arising problems in the research of SU UMa-type dwarf novae: 1) how do EI Psc and V485 Cen evolve as a cataclysmic variable?, 2) is the early superhump a particular phenomenon for WZ Sge-type dwarf novae?, and 3) what parameters determine variations of the superhump period?
We studied the Kepler light curves of three SU UMa-type dwarf novae. Both the background dwarf nova of KIC 4378554 and V516 Lyr showed a combination of precursor-main superoutburst, during which superhumps always developed on the fading branch of the
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 superhump period are found to be composed of three distinct stages: early evol
SU UMa stars are characterized by superoutbursts which are brighter at maximum light and which last much longer than the more frequent ordinary outbursts of these dwarf novae. Although there are now more than 1180 SU UMa type dwarf novae catalogued,
We present time-resolved CCD photometry of a dwarf nova NSV 4838 (UMa 8, SDSS J102320.27+440509.8) during the 2005 June and 2007 February outburst. Both light curves showed superhumps with a mean period of 0.0699(1) days for the 2005 outburst and 0.0
Continuing the project described by Kato et al. (2009, PASJ, 61, S395, arXiv/0905.1757), we collected times of superhump maxima for 102 SU UMa-type dwarf novae observed mainly during the 2017 season and characterized these objects. WZ Sge-type stars