Photometric Studies of New Southern SU UMa-type dwarf novae, FL Triangulum Australe and CTCV J0549-4921

TL;DR

This study presents time-resolved photometry of two newly discovered SU UMa-type dwarf novae, revealing superhump periods and behaviors that relate them to WZ Sge and short-period SU UMa stars, and discusses their outburst characteristics.

Contribution

First detailed photometric analysis of FL TrA and CTCV J0549-4921, establishing their SU UMa nature and superhump properties, and linking their behaviors to known dwarf nova subclasses.

Findings

FL TrA shows superhumps with a period of 0.59897 days.

CTCV J0549-4921 exhibits small outburst amplitude (~4.5 mag).

The superhump period variation in FL TrA resembles that of WZ Sge stars.

Abstract

We report time-resolved optical CCD photometry on newly discovered SU UMa-type dwarf novae, FL TrA and CTCV J0549-4921. During the 2006 August outburst, we detected superhumps with a period of 0.59897(11) days for FL TrA, clarifying the SU UMa nature of the system. On the first night of our observations on FL TrA, the object showed no superhumps. This implies that it takes a few days for full development of superhumps. The superhump period variation diagram of FL TrA was similar to that observed in some WZ Sge stars and short period SU UMa-type stars. This indicates that the system is closely related to WZ Sge stars and SU UMa stars having short orbital periods. For CTCV J0549-4921, the candidates of the mean superhump period are 0.083249(10) days and 0.084257(8) days, respectively. Due to a lack of the observations, we cannot determine the true superhump period, but the latter period is favorable. Using the ASAS-3 archive, it turned out that the system shows only four outbursts over the past 6 years. The outburst amplitude of CTCV J0549-4921 was relatively small, with about 4.5 mag. One possibility is that mass evaporation may play a role during quiescence.