Measuring the superhump period of the dwarf nova RX J1715.6+6856

TL;DR

This study reports the first superoutburst observation of dwarf nova RX J1715.6+6856, measuring its superhump period and analyzing its outburst behavior, confirming its classification as an SU UMa type dwarf nova.

Contribution

The paper provides the first measurement of the superhump period and superhump period excess for RX J1715.6+6856, establishing its membership in the SU UMa class.

Findings

Superhump period Psh = 0.07086 days

Superhump period excess epsilon = 0.038

Approximately one outburst per month

Abstract

We report unfiltered CCD observations of the first confirmed superoutburst of the dwarf nova RX J1715.6+6856 in August 2009. At quiescence the star was magnitude 18.3 (CCD, clear). The outburst amplitude was at least 2.4 magnitudes and it lasted at least 6 days, although the first part of the outburst was probably missed. Analysis of the light curve revealed superhumps with peak-to-peak amplitude of 0.1 magnitude, thereby showing it to be a member of the SU UMa family. The mean superhump period was Psh = 0.07086(78) d with a superhump period excess of epsilon = 0.038 and an estimated mass ratio q = 0.167. In the final stages of the outburst, as the star approached quiescence, the superhumps disappeared to be replaced by a modulation corresponding to the orbital period. The star was regularly monitored between August 2007 and September 2009 revealing a total of 12 outbursts, with an outburst frequency of approximately once per month.