Kilo-Second Quasi-Periodic Oscillations in the Cataclysmic Variable DW Cancri
Abstract
Our photometric monitoring revealed that DW Cnc, which was originally classified as a dwarf nova (V=15--17.5), remained at a bright state of Rc=14.68+/-0.07 for 61 days. In conjunction with optical spectra lacking a strong He II emission line, we propose that the object is not a dwarf nova, but a non-magnetic nova-like variable. Throughout our monitoring, the object showed strong quasi-periodic oscillations (QPOs) with amplitudes reaching about 0.3 mag. Our period analysis yielded a power spectrum with two peaks of QPOs, whose center periods are 37.5+/-0.1 and 73.4+/-0.4 min and, furthermore, with a significant power in frequencies lower than the QPOs. DW Cnc is a unique cataclysmic variable in which kilo-second QPOs were continuously detected for 61 days. We propose two possible interpretations of DW Cnc: (i) A permanent superhumper below the period minimum of hydrogen-rich cataclysmic variables. (ii) A nova-like variable having an orbital period over 3 hours. In this case, the QPOs may be caused by trapped disk oscillations.
Cite
@article{arxiv.astro-ph/0203247,
title = {Kilo-Second Quasi-Periodic Oscillations in the Cataclysmic Variable DW Cancri},
author = {M. Uemura and T. Kato and R. Ishioka and R. Novak and J. Pietz},
journal= {arXiv preprint arXiv:astro-ph/0203247},
year = {2015}
}
Comments
6 pages, 4 figures, PASJ in press