Outburst of V592 Her, 1998

Gary Poyner

V592 Herculis was discovered in outburst on Sonneberg plates by Richter in June 1968. An examination of the light curve by H. Duerbeck, suggested that Nova Her 68 resembled that of the X-ray Nova V616 Mon. A preliminary t3 of 27d was associated with the decline.1

A second outburst was picked up again on photographic plates on May 12 1986. However this was a poorly covered event, and no details as to the type of outburst could be derived from available information. Following this second outburst, the star became a target for amateur DNe observers, and a more comprehensive monitoring programme was created. This included V592 Her being added to the UK Recurrent Objects Programme.

An unconfirmed brightening was reported by P. Ouimet on May 25.123 UT 1996 at 15.3, following an unfiltered CCD image.2 However a follow up CCD image taken by M. Iida on May 26.512 UT recorded nothing brighter than 15.8.

The recent outburst was detected by the Finnish observer Timo Kinnunen on Aug 26.835 UT at visual magnitude 12.0. This was confirmed on Aug 27.181 UT by Lance Shaw in California. It appears from observations reported to VSNET that maximum brightness occurred on the day of the detection.

Superhumps were detected by Gordon Garrard on September 2nd, using time series CCD photometry. The amplitude of the superhumps being 0.3 mag, with a period of 83 minutes - the amplitude decaying to 0.1 magnitude by September 7th.

Left: CCD by J Mackey - hazy conditions

The large outburst amplitude (>9 mags) & recurrence period suggests that V592 Her is a member of the rare UGWZ class. Spectral analysis by R. Mennickent supports this classification. Presently (Sep 16th) the star has reached a plateau stage, being steady around 16th magnitude. A comparison with historic outbursts of WZ Sge & AL Com may suggest that this outburst is not yet over!

Various VSNET reports have provided the source material for this review.

1: A Reference Catalogue and Atlas of Galactic Novae. H. Duerbeck.
2: Private communication.