V364 Peg - a new UGSU-type dward nova near the period gap

Following Patrick Schmeer's announcement [cba-news, dd. Nov 19, 2004] of an outburst detection of V364 Peg, on CCD images taken on Nov 19.088 UT, I started an unfiltered time-series photometry session on this object, at CBA Belgium Observatory. Observations were made between 17h UT (Nov 19, 2004) and 21h35m UT, yielding a total of 193 CCD images, using an SBIG ST-7XME camera.

V364 Peg light curve on Nov 19/20, 2004 based on unfiltered CCD observations,
obtained at CBA Belgium Observatory

The resulting light curve (see above) clearly shows the presence of well developed superhumps with an amplitude of about 0.3 mag. This securely classifies V364 Peg as a new member of the UGSU-type dwarf novae. Using the ANOVA period determination method of Peranso, I find a superhump period of 0.0882 +/- 0.0070 d (2.12 hours), which is *very* close to the lower limit of the so called period gap.

ANOVA period window yielding superhump period of 0.0882 d.

Phase diagram for V364 Peg

V364 Peg was discovered during the supernova survey at the Beijing Astronomical Observatory [Qiu et al. IAUC, No. 6746].  The object was classified as a suspected UGSU-type dwarf nova, based on a limited set of observations obtained at Kyoto University on Nov 19, 1997 [IBVS 4776], showing an hump-like feature. Due to the limited timespan of the observations, the article was not conclusive on the superhump period neither.

Given the long orbital period of this dwarf nova, it is an interesting target for follow-up observations





Copyright © 2004 - Tonny Vanmunster.