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; N. Wells; A. Sosnovskij; K. Antonyuk; A. Simon; N. Pit; C. Littlefield; H. Itoh; S. Kiyota; T. Tordai; P. Dubovsky; T. Vanmunster; G. Stone; T. Kato; A. Sergeev; V. Godunova; E. Lyumanov; O. Antonyuk; A. Baklanov; Ju. Babina; K. Isogai; Ya. Romanyuk; V. Troianskyi; V. Kashuba

arXiv · 1907.00623

ASASSN-18fk: A new WZ Sge-type dwarf nova with multiple rebrightenings and a new candidate for a superhumping intermediate polar

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Abstract

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 15 sites during ~70 nights within a three-month interval. Observations covered the main outburst, six rebrightenings and 50-d decline to a near-quiescent state. We identify ASASSN-18fk as WZ Sge-type dwarf nova with multiple rebrightenings and show the evolution of the 0.06-d superhump period over all stages of the superoutburst. A strong 22-min brightness modulation that superimposed on superhumps is found during rebrightenings and decline. Some evidence of this modulation in a form of a sideband signal is detected during the very onset of the outburst. We interpret the 22-min modulation as a spin period of the white dwarf and suggest that ASASSN-18fk is a good candidate for a superhumping intermediate polar.

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E. Pavlenko, K. Niijima, P. Mason, N. Wells, A. Sosnovskij, K. Antonyuk, A. Simon, N. Pit, C. Littlefield, H. Itoh, S. Kiyota, T. Tordai, P. Dubovsky, T. Vanmunster, G. Stone, T. Kato, A. Sergeev, V. Godunova, E. Lyumanov, O. Antonyuk, A. Baklanov, Ju. Babina, K. Isogai, Ya. Romanyuk, V. Troianskyi, V. Kashuba. 2019-07-01. ASASSN-18fk: A new WZ Sge-type dwarf nova with multiple rebrightenings and a new candidate for a superhumping intermediate polar. https://arxiv.org/abs/1907.00623

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