Discovery and outburst characteristics of the dwarf nova ASAS J224349+0809.5

• Published in: Journal of the British Astronomical Association 2011-06, Vol.121 (3), p.155
• Main Authors: Shears, Jeremy, Wils, Patrick, Bolt, Greg, Hambsch, Franz-Josef, Krajci, Tom, Miller, Ian, Sabo, Richard, Staels, Bart
• Format: Article
• Language: English
• ISSN: 0007-0297

We report the discovery of a new dwarf nova and observations of its first confirmed superoutburst during 2009 October. The outburst amplitude was 6 magnitudes. The main outburst lasted 17 days and was followed 4 days later by a remarkable rebrightening. Superhumps were present during the main outburst, which confirms that it belongs to the SU UMa family. Initially the mean superhump period was [P.sub.sh] = 0.06965(l7)d, but analysis of the O-C residuals showed a dramatic evolution in [P.sub.sh] during the outburst. During the first two-thirds of the plateau phase the period increased with d[P.sub.sh]/dt = + l.24(5)x [10.sup.-3]. There was then an abrupt change following which the period decreased with d[P.sub.sh]/dt = -l.0l(9)x [10.sup.-3]. The amplitude of the superhumps also varied, with a maximum amplitude near the beginning of the outburst and a second maximum corresponding to the discontinuity in [P.sub.sh]. Analysis of archival data showed that outbursts also occurred in 2005 October, 2006 June and 2007 June. Assuming that the superoutbursts are periodic, we estimate that the outburst period is around 450 days.