Kilo-Second Quasi-Periodic Oscillations in the Cataclysmic Variable DW Cancri
Abstract
Our photometric monitoring revealed that DWCnc, which was originally classified as a dwarf nova (V=15 - 17.5) remained at a bright state of Rc=14.68 +/- 0.07 for 61days. 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 0.3mag. 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. DWCnc is a unique cataclysmic variable in which kilo-second QPOs were continuously detected for 61days. We propose two possible interpretations of DWCnc: (i) A permanent superhumper below the period minimum of hydrogen-rich cataclysmic variab les. (ii) A nova-like variable having an orbital period over 3hours. In this case, the QPOs may be caused by trapped disk oscillations.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- April 2002
- DOI:
- 10.1093/pasj/54.2.299
- arXiv:
- arXiv:astro-ph/0203247
- Bibcode:
- 2002PASJ...54..299U
- Keywords:
-
- accretion;
- accretion disks;
- stars: binaries: close;
- stars: individual (DW Cnc);
- Astrophysics
- E-Print:
- 6 pages, 4 figures, PASJ in press