RX J1643.7+3402  -  A bright nova-like CV in the period gap

RX J1643.7+3402, located at RA = 16h43m45.72s, Dec = +34°02'40.2" (J2000.0) is a ROSAT X-ray source, that was discovered as a bright (V ~12.6) cataclysmic variable by A. Michaelian et al. (A. M. Mickaelian, S. K. Balayan, S. A. Ilovaisky, C. Chevalier, M.-P. Véron-Cetty and P. Véron, A&A 381, 894-904 (2002)). 

Michaelian reported spectroscopic and photometric observations,  showing it to be a novalike variable sharing some of the characteristics of the SW Sex sub-class of novalike CVs. They announced a spectroscopic period of either 2.575h or 2.885h, within the period "gap". They furthermore reported a photometric modulation with a probable period of 2.595h and an amplitude of ~0.1 mag in V, that was present on most nights and could either be a "positive" or a "negative" superhump modulation (depending on the exact spectroscopic period), indicating the presence of a precessing accretion disk in this system. In addition, they observed rapid variations of 0.1 to 0.2 mag amplitude in V, repeating with a time scale of ~15 min.

With these 'credentials', the object evidently attracted the attention of other professional astronomers, including Joe Patterson (Columbia University, CBA, New York) who launched an international observing campaign in April 2002, to study RX J1643.7+3402 in full detail, using the telescopes of the CBA network (high-speed time series photometry).

We here report unfiltered CCD observations of RX J1643.7+3402, obtained at CBA Belgium Observatory in April 2002. The object definitely is amongst the most interesting CV's we have ever studied, showing a complex variety of periodicities..






Copyright © 2002 - Tonny Vanmunster.