On supercycle lengths of active SU UMa stars

TL;DR

This study analyzes the increasing supercycle lengths of active SU UMa stars, revealing a decline in their mass transfer rates over decades, which provides insights into their evolutionary processes.

Contribution

It presents the first detailed observational evidence of supercycle length increase in active SU UMa stars and estimates their future evolution.

Findings

Supercycle lengths have been steadily increasing over decades.

Mass transfer rates in these stars are decreasing.

The results have implications for understanding dwarf novae evolution.

Abstract

We performed a detailed analysis of extensive photometric observations of a sample of most active dwarf novae, that is SU UMa stars which are characterised by supercycle lengths shorter than 120 days. We found the observational evidence that supercycle lengths for these objects have been constantly increasing over the past decades, which indicates that their mean mass transfer rates have been decreasing during that time. This seems to be a common feature for this type of stars. We present numerical results in each case and estimate time scales of future development of these systems. This study is important in the context of evolution of dwarf novae stars and perhaps other cataclysmic variables.