86 citations · 335 across the 23 of their papers we have counts for
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2021 superoutburst of WZ Sge-type dwarf nova V627 Pegasi lacks an early superhump phase
Yusuke Tampo, Taichi Kato, Naoto Kojiguchi +27
Superoutbursts in WZ Sge-type dwarf novae (DNe) are characterized by both early superhumps and ordinary superhumps originating from the 2:1 and 3:1 resonances, respectively. Howeve…
On the nature of the anomalous event in 2021 in the dwarf nova SS Cygni and its multi-wavelength transition
Mariko Kimura, Shinya Yamada, Nozomi Nakaniwa +20
SS Cyg has long been recognized as the prototype of a group of dwarf novae that show only outbursts. However, this object has entered a quite anomalous event in 2021, which at firs…
Spectroscopic and Photometric Observations of Dwarf Nova Superoutbursts by the 3.8 m Telescope Seimei and the Variable Star Network
Yusuke Tampo, Keisuke Isogai, Naoto Kojiguchi +59
We present spectroscopic and photometric observations of 17 dwarf-nova superoutbursts obtained by KOOLS-IFU mounted on the 3.8 m telescope Seimei at Okayama Observatory of Kyoto Un…
Multi-wavelength photometry during the 2018 superoutburst of the WZ Sge-type dwarf nova EG Cancri
Mariko Kimura, Keisuke Isogai, Taichi Kato +45
We report on the multi-wavelength photometry of the 2018 superoutburst in EG Cnc. We have detected stage A superhumps and long-lasting late-stage superhumps via the optical photome…
First Detection of Two Superoutbursts during Rebrightening Phase of a WZ Sge-type Dwarf Nova: TCP J21040470+4631129
Yusuke Tampo, Kojiguchi Naoto, Keisuke Isogai +51
We report photometric and spectroscopic observations and analysis of the 2019 superoutburst of TCP J21040470+4631129. This object showed a 9-mag superoutburst with early superhumps…
IW And-Type State in IM Eridani
Taichi Kato, Yasuyuki Wakamatsu, Naoto Kojiguchi +20
IW And stars are a recently recognized group of dwarf novae which are characterized by a repeated sequence of brightening from a standstill-like phase with damping oscillations fol…
ASASSN-18fk: A new WZ Sge-type dwarf nova with multiple rebrightenings and a new candidate for a superhumping intermediate polar
E. Pavlenko, K. Niijima, P. Mason +23
We present the result of a multi-longitude campaign on the photometric study of the dwarf nova ASASSN-18fk during its superoutburst in 2018. It was observed with 18 telescopes at 1…
Discovery of Standstills in the SU UMa-Type Dwarf Nova NY Serpentis
Taichi Kato, Elena P. Pavlenko, Nikolaj V. Pit +40
We found that the SU UMa-type dwarf nova NY Ser in the period gap [orbital period 0.097558(6) d] showed standstills twice in 2018. This is the first clear demonstration of a stands…
Asynchronous polar V1500 Cyg: orbital, spin and beat periods
E. P. Pavlenko, P. A. Mason, A. A. Sosnovskij +7
The bright Nova Cygni 1975 is a rare nova on a magnetic white dwarf (WD). Later it was found to be an asynchronous polar, now called V1500 Cyg. Our multisite photometric campaign o…
On the Nature of Long-Period Dwarf Novae with Rare and Low-Amplitude Outbursts
Mariko Kimura, Taichi Kato, Hiroyuki Maehara +35
There are several peculiar long-period dwarf-nova like objects, which show rare, low-amplitude outbursts with highly ionized emission lines. 1SWASP J162117441254, BD Pav, and V3…
ASASSN-16eg: New candidate of long-period WZ Sge-type dwarf nova
Yasuyuki Wakamatsu, Keisuke Isogai, Mariko Kimura +19
We report on our photometric observations of the 2016 superoutburst of ASASSN-16eg. This object showed a WZ Sge-type superoutburst with prominent early superhumps with a period of…
OT J002656.6+284933 (CSS101212:002657+284933): An SU UMa-Type Dwarf Nova with Longest Superhump Period
Taichi Kato, Tamas Tordai, Colin Littlefield +17
We observed the 2016 outburst of OT J002656.6+284933 (CSS101212:002657+284933) and found that it has the longest recorded [0.13225(1) d in average] superhumps among SU UMa-type dwa…
RZ Leonis Minoris Bridging between ER Ursae Majoris-Type Dwarf Nova and Novalike System
Taichi Kato, Ryoko Ishioka, Keisuke Isogai +64
We observed RZ LMi, which is renowned for the extremely (~19d) short supercycle and is a member of a small, unusual class of cataclysmic variables called ER UMa-type dwarf novae, i…
Superoutburst of CR Bootis: Estimation of Mass Ratio of a typical AM CVn star by Stage A Superhumps
Keisuke Isogai, Taichi Kato, Tomohito Ohshima +31
We report on two superoutbursts of the AM CVn-type object CR Boo in 2014 April--March and 2015 May--June. A precursor outburst acompanied both of these superoutbursts. During the r…
ASASSN-15jd: WZ Sge-type star with intermediate superoutburst between single and double ones
Mariko Kimura, Keisuke Isogai, Taichi Kato +21
We present optical photometry of a WZ Sge-type dwarf nova (DN), ASASSN-15jd. Its light curve showed a small dip in the middle of the superoutburst in 2015 for the first time among…
OT J075418.7+381225 and OT J230425.8+062546: Promising Candidates for the Period Bouncer
Chikako Nakata, Taichi Kato, Daisaku Nogami +15
We report on photometric observations of two dwarf novae, OT J075418.7+381225 and OT J230425.8+062546, which underwent superoutburst in 2013 (OT J075418) and in 2011 (OT J230425).…
NY Serpentis: SU UMa-Type Nova in the Period Gap with Diversity of Normal Outbursts
Elena P. Pavlenko, Taichi Kato, Oksana I. Antonyuk +16
We present photometric study of NY Ser, an in-the-gap SU UMa-type nova, in 2002 and 2013. We determined the duration of the superoutburst and the mean superhump period to be 18 d a…
Superoutburst of SDSS J090221.35+381941.9: First Measurement of Mass Ratio in an AM CVn-Type Object using Growing Superhumps
Taichi Kato, Tomohito Ohshima, Denis Denisenko +36
We report on a superoutburst of the AM CVn-type object SDSS J090221.35+381941.9 [J0902; orbital period 0.03355(6) d] in 2014 March-April. The entire outburst consisted of a precurs…
Study of Negative and Positive Superhumps in ER Ursae Majoris
Tomohito Ohshima, Taichi Kato, Elena Pavlenko +45
We carried out the photometric observations of the SU UMa-type dwarf nova ER UMa during 2011 and 2012, which showed the existence of persistent negative superhumps even during the…
Discovery of Negative Superhumps during a Superoutburst of January 2011 in ER Ursae Majoris
Tomohito Ohshima, Taichi Kato, Elena P. Pavlenko +19
We report on a discovery of "negative" superhumps during the 2011 January superoutburst of ER UMa. During the superoutburst which started on 2011 January 16, we detected negative s…