DT Oct (NSV 10934)

DT Oct was first bought to my attention when a call for observations appeared in vsnet chat 3340.

“Another large-amplitude NSV object likely identified with a strong ROSAT source.  Potential CV?”

The cataloged range of variability was 11.2 to <15.0 p. The object was identified with a bright ROSAT X-ray source (1RXS J184050.3−834305).

DT Oct was added to my list of CV’s and I detected an outburst in March 13th, 2001 which was the first-ever visual detection of this potential CV. Further visual outbursts were detected up to July 2002 which showed a fading rate of 1.0  magnitude within 3 days of the outburst maximum. The short outbursts were occurring at irregular intervals of around 40 – 60 days.  See link.  2002A&A…396..929K

On January 2nd 2003 I detected an outburst at magnitude 15.0. I observed this outburst throughout the night and it rose to magnitude 11.9 being the brightest outburst observed so far. A time-resolved CCD photo-metric campaign started on the next night of this detection. Superhumps were detected on January 4th thus establishing DT Oct to be a new SU-UMa- type dwarf nova.

DT Oct outburst image taken by Peter Nelson from a normal fading outburst in 2002.


DT OCT superoutburst in March 2013 by Arto Oksanen, Finland

DT Oct arto

Light curve of DT Oct showing all of my visual outburst observations.

DT Oct

DT Oct has normal outbursts around 40-60 days although on one occasion a normal outburst was within 18 days. The superoutburst cycle looks like a 1 year recurrence time with a normal outburst following a superoutburst around 50 days.

Co-authored papers on DT Oct (NSV 10934)

Two X-ray bright cataclysmic variables with unusual activities: GZ Cnc and NSV 10934 2002A&A…396..929K

NSV 10934: an Unusual ROAST-Selected Dwarf Nova: An Analogous Object to HT Cam? arXiv:astro-ph/0207611v1


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