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ASASSN-16eg: New candidate for a long-period WZ Sge-type dwarf nova
Tekijät: Yasuyuki Wakamatsu, Keisuke Isogai, Mariko Kimura, Taichi Kato, Tonny Vanmunster, Geoff Stone, Tamás Tordai, Michael Richmond, Ian Miller, Arto Oksanen, Hiroshi Itoh, Hidehiko Akazawa, Seiichiro Kiyota, Enrique de Miguel, Elena P. Pavlenko, irill A. Antonyuk, Oksana I. Antonyuk, Vitaly V. Neustroev, George Sjoberg, Pavol A. Dubovsky, Roger D. Pickard, Daisaku Nogami
Kustantaja: OXFORD UNIV PRESS
Julkaisuvuosi: 2017
Journal: Publications- Astronomical Society of Japan
Tietokannassa oleva lehden nimi: PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
Lehden akronyymi: PUBL ASTRON SOC JPN
Artikkelin numero: 89
Vuosikerta: 69
Numero: 6
Sivujen määrä: 9
ISSN: 0004-6264
eISSN: 2053-051X
DOI: https://doi.org/10.1093/pasj/psx094
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 0.075478(8) d and a post-superoutburst rebrightening. During the superoutburst plateau, it showed ordinary superhumps with a period of 0.077880(3) d and a period derivative of 10.6(1.1) x 10(-5) in stage B. The orbital period (P-orb), which is almost identical with the period of the early superhumps, is exceptionally long for a WZ Sge-type dwarf nova. The mass ratio (q = M-2/M-1) estimated from the period of developing (stage A) superhumps is 0.166(2), which is also too large for a WZ Sge-type dwarf nova. This suggests that the 2 : 1 resonance can be reached in such high-q systems, contrary to our expectation. Such conditions are considered to be achieved if the mass-transfer rate is much lower than those in typical SU UMa-type dwarf novae that have comparable orbital periods to ASASSN-16eg, and a resultant accumulation of a large amount of matter on the disk is realized at the onset of an outburst. We examined other candidates for long-period WZ Sge-type dwarf novae for their supercycles, which are considered to reflect the mass-transfer rate, and found that V1251 Cyg and RZ Leo have longer supercycles than those of other WZ Sge-type dwarf novae. This result indicates that these long-period objects including ASASSN-16eg have a low mass-transfer rate in comparison to other WZ Sge-type dwarf novae.
