Multi-wavelength photometry during the 2018 superoutburst of the WZ Sge-type dwarf nova EG Cancri. (arXiv:2008.11871v1 [astro-ph.SR])

Multi-wavelength photometry during the 2018 superoutburst of the WZ Sge-type dwarf nova EG Cancri. (arXiv:2008.11871v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kimura_M/0/1/0/all/0/1">Mariko Kimura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Isogai_K/0/1/0/all/0/1">Keisuke Isogai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kato_T/0/1/0/all/0/1">Taichi Kato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kojiguchi_N/0/1/0/all/0/1">Naoto Kojiguchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wakamatsu_Y/0/1/0/all/0/1">Yasuyuki Wakamatsu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ohnishi_R/0/1/0/all/0/1">Ryuhei Ohnishi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sugiura_Y/0/1/0/all/0/1">Yuki Sugiura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsumoto_H/0/1/0/all/0/1">Hanami Matsumoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sumiya_S/0/1/0/all/0/1">Sho Sumiya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ito_D/0/1/0/all/0/1">Daiki Ito</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nikai_K/0/1/0/all/0/1">Kengo Nikai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsumoto_K/0/1/0/all/0/1">Katsura Matsumoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shugarov_S/0/1/0/all/0/1">Sergey Yu. Shugarov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kathysheva_N/0/1/0/all/0/1">Natalia Kathysheva</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Itoh_H/0/1/0/all/0/1">Hiroshi Itoh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dubovsky_P/0/1/0/all/0/1">Pavol A. Dubovsky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kudzej_I/0/1/0/all/0/1">Igor Kudzej</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Akitaya_H/0/1/0/all/0/1">Hiroshi Akitaya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oide_K/0/1/0/all/0/1">Kohei Oide</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kanai_T/0/1/0/all/0/1">Takahiro Kanai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ishioka_C/0/1/0/all/0/1">Chihiro Ishioka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oasa_Y/0/1/0/all/0/1">Yumiko Oasa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vanmunster_T/0/1/0/all/0/1">Tonny Vanmunster</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oksanen_A/0/1/0/all/0/1">Arto Oksanen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tordai_T/0/1/0/all/0/1">Tamás Tordai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Murata_K/0/1/0/all/0/1">Katsuhiro L. Murata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shiraishi_K/0/1/0/all/0/1">Kazuki Shiraishi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Adachi_R/0/1/0/all/0/1">Ryo Adachi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oeda_M/0/1/0/all/0/1">Motoki Oeda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tachibana_Y/0/1/0/all/0/1">Yutaro Tachibana</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kiyota_S/0/1/0/all/0/1">Seiichiro Kiyota</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pavlenko_E/0/1/0/all/0/1">Elena P. Pavlenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Antonyuk_K/0/1/0/all/0/1">Kirill Antonyuk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Antonyuk_O/0/1/0/all/0/1">Oksana Antonyuk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pit_N/0/1/0/all/0/1">Nikolai Pit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sosnovskij_A/0/1/0/all/0/1">Aleksei Sosnovskij</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Babina_J/0/1/0/all/0/1">Julia Babina</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baklanov_A/0/1/0/all/0/1">Alex Baklanov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kawabata_K/0/1/0/all/0/1">Koji S. Kawabata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kawabata_M/0/1/0/all/0/1">Miho Kawabata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nakaoka_T/0/1/0/all/0/1">Tatsuya Nakaoka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yamanaka_M/0/1/0/all/0/1">Masayuki Yamanaka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kasai_K/0/1/0/all/0/1">Kiyoshi Kasai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miller_I/0/1/0/all/0/1">Ian Miller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brincat_S/0/1/0/all/0/1">Stephen M. Brincat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_W/0/1/0/all/0/1">Wei Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sasada_M/0/1/0/all/0/1">Mahito Sasada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nogami_D/0/1/0/all/0/1">Daisaku Nogami</a>

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 photometry and have constrained the binary mass ratio and its
possible range. The median value of the mass ratio is 0.048 and the upper limit
is 0.057, which still implies that EG Cnc is one of the possible candidates for
the period bouncer. This object also showed multiple rebrightenings in this
superoutburst, which are the same as those in its previous superoutburst in
1996–1997 despite the difference in the main superoutburst. This would
represent that the rebrightening type is inherent to each object and is
independent of the initial disk mass at the beginning of superoutbursts. We
also found that $B-I$ and $J-K_{rm S}$ colors were unusually red just before
the rebrightening phase and became bluer during the quiescence between
rebrightenings, which would mean that the low-temperature mass reservoir at the
outermost disk accreted with time after the main superoutburst. Also, the
ultraviolet flux was sensitive to rebrightenings as well as the optical flux,
and the $U-B$ color became redder during the rebrightening phase, which would
indicate that the inner disk became cooler when this object repeated
rebrightenings. Our results thus basically support the idea that the cool mass
reservoir in the outermost disk is responsible for rebrightenings.

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