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

TL;DR

This paper reports the discovery of a new dwarf nova, ASAS J224349+0809.5, its superoutburst characteristics, superhump period evolution, and estimates its outburst cycle, contributing new observational data to the study of SU UMa-type dwarf novae.

Contribution

It provides the first confirmed superoutburst observation of this dwarf nova and details the evolution of superhump periods during the outburst, which is novel.

Findings

Superoutburst lasted 17 days with a 6 magnitude amplitude.

Superhump period showed a dramatic evolution during the outburst.

Estimated outburst cycle is approximately 450 days.

Abstract

We report the discovery of a new dwarf nova and our 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 Psh = 0.06965(17) d, but analysis of the O-C residuals showed a dramatic evolution in Psh during the outburst. During the first two-thirds of the plateau phase the period increased with dPsh/dt = +1.24(5) x 10-3. There was then an abrupt change following which the period decreased with dPsh/dt = -1.01(9) x 10-3. 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 Psh. Analysis of archival data showed outbursts also occurred in October 2005, June 2006 and June 2007. Assuming that the superoutbursts are periodic, we estimate that the outburst period is around 450 days.