2017/08/28 by Yasuyuki Wakamatsu, Keisuke Isogai, Mariko Kimura +19
Physics and Astronomy · #Accretion (finance) #Accretion disc #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Cataclysmic variable star #Circumbinary planet #Dwarf nova #Gamma-ray bursts and supernovae #Orbital period #Period (music) #astro-ph.SR
paper · pdf · doi:10.1093/pasj/psx094
9 pages, 5 figures
openalex publication_date 2017/08/28 · openalex created_date 2017/09/15 · arxiv created 2017/09/22 · arxiv updated 2017/09/25 · openalex updated_date 2026/08/05
Abstract 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) × 10−5 in stage B. The orbital period (Porb), 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 = M2/M1) 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.