SW Sex stars, old novae, and the evolution of cataclysmic variables

TL;DR

This paper explores the peculiar characteristics of SW Sex stars and old novae in the context of cataclysmic variable evolution, highlighting the potential for hibernation phases post-nova outbursts.

Contribution

It introduces the idea that some old novae may enter a hibernation state, challenging existing classifications of high and low mass transfer systems.

Findings

Old novae in the period gap may resemble low mass transfer systems.

Some systems show signs of hibernation after nova outbursts.

The study provides preliminary insights into CV evolution and hibernation phases.

Abstract

The population of cataclysmic variables with orbital periods right above the period gap are dominated by systems with extremely high mass transfer rates, the so-called SW Sextantis stars. On the other hand, some old novae in this period range which are expected to show high mass transfer rate instead show photometric and/or spectroscopic resemblance to low mass transfer systems like dwarf novae. We discuss them as candidates for so-called hibernating systems, CVs that changed their mass transfer behaviour due to a previously experienced nova outburst. This paper is designed to provide input for further research and discussion as the results as such are still very preliminary.