January/February 2003 observations of GZ Cnc

Below is an overview of (unfiltered) CCD observations of GZ Cnc, collected at CBA Belgium Observatory in January & February  2003. Equipment used was a 0.35-m f/6.3 SCT telescope and SBIG ST-7 CCD camera.

My first night of observations was January 30/31, 2003, when sky conditions were quite bad, with only short breaks between long spells of clouds. The resulting light curve nevertheless confirms the findings of the VSNET Collaboration team (vsnet-campaign-dn 3376), who noticed large-amplitude humps with a superhump-like profile, next to short-period modulations with a low amplitude. 

The night of January 31/February 01, 2003 had better atmospheric conditions, with long and stable clear periods. The variable was monitored for 6.0 hours, and the resulting light curve is amongst the most interesting, but also most complex ones I have seen in months (see below). At the beginning of the session, GZ Cnc was fading by about 0.5 mag, as part of what seemed to be the slope of a superhump. The subsequent rise showed a first remarkable and symmetric dip of about 0.35 mag around JD +2671.46. Apparently, this was the start of a gradual brightening of the object, which continued till the end of the session. However, this rising trend was superimposed with lots of irregular and short period oscillations about 0.1 - 0.2 mag in amplitude. Large amplitude modulations started to appear again in the light curve around JD +2671.57, when GZ Cnc showed an amazing, eclipse-alike 0.8 magnitude drop. After that, high amplitude variations continued to exist until the end of my observing session. What a nice show this variable puts on ! 





Copyright © 2003 - Tonny Vanmunster.