DW Cnc : Curious short-term variations

M. Reszelski reported a possible brightening to 14.5mag of this poorly studied cataclysmic variable on February 18. This indicates an outburst occurred, but there was no previous firm faint state observation (vsnet-campaign-dn 514, 527). T. Vanmunster mentioned the object is always around 14.5+/- 0.5 mag, and this activity may not be a genuine outburst (vsnet-campaign-dn 531). The Ouda team detected short-term variations whose amplitudes are typically 0.3mag and period slightly shorter than 0.03day. T. Kato reported that the period may reflect either the spin period of an intermediate polar, or the orbital/superhump period of an ultrashort-period binary (vsnet-campaign 815, 816). R. Novak sent his data to the Kyoto team. His data confirmed the similar periodicity previously reported from the Kyoto and Ouda data. On March 20, T. Kato reported that the combined data set shows 0.0275 day or its double periodicity (vsnet-campaign 818). On March 22, he again reported that the data including the additional one show a very gradual fading trend (0.04 mag/d) which may resemble those of slowly fading plateau of ER UMa stars. The period analysis yielded multiple period candidates at 0.0756 d, 0.0536 d, 0.0488 d, and 0.0276 d. He noticed that there may be a hint of beats between these periods, but if any shorter one of them is a superhump/orbital period, this system may be an extremely rare system close to the CV period minimum, or below the period (vsnet-campaign 822). The combined data showed 0.053 and 0.027 day period, but their confidence level is low (vsnet-campaign 835). R. Novak's data on mid-April showed strong modulations with a period of 0.029 d (vsnet-campaign-dn 655). M. Uemura reported that the object has remained the brightness over one month. The time-series monitoring campaign by the Kyoto team, R. Novak, and J. Pietz yields the periodicity of 0.04855 or 0.0268 d. (vsnet-campaign 862). The object was still in bright state in the latter half of 2001 (vsnet-campaign-dn 1874).

Other related articles: vsnet-campaign-dn 596, 602, 605, 621, 624, 650, 652, 661, vsnet-campaign-nl 52, vsnet-campaign 824, 834, 820, 825

Sequence and chart reported by B. Sumner: http://joevp.20m.com/cgi-bin/i/charts/hscharts/South_up/Cnc_DW_sxn.jpg,
Data in Amateur Data Archvie: http://ada.astronomy.cz

General Information on This Object