86 citations · 335 across the 23 of their papers we have counts for
23 papers
Spectroscopic and photometric study of the new eclipsing polar Gaia23cer
A. I. Kolbin, E. P. Pavlenko, V. Yu. Kochkina +11
We present the results of the optical study of the new eclipsing polar Gaia23cer. We analyzed the brightness variability of the polar in high ($\langle r \rangle \approx 16.5\mathr…
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…
Optical Variability Correlated with X-ray Spectral Transition in the Black-Hole Transient ASASSN-18ey = MAXI J1820+070
Keito Niijima, Mariko Kimura, Yasuyuki Wakamatsu +49
How a black hole accretes matter and how this process is regulated are fundamental but unsolved questions in astrophysics. In transient black-hole binaries, a lot of mass stored in…
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…
Repetitive Patterns in Rapid Optical Variations in the Nearby Black-hole Binary V404 Cygni
Mariko Kimura, Keisuke Isogai, Taichi Kato +65
How black holes accrete surrounding matter is a fundamental, yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion…
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…