TESS light curves of cataclysmic variables -- II: Superhumps in old novae and novalike variables

TL;DR

This study utilizes TESS light curves to analyze superhump phenomena in old novae and novalike variables, providing a comprehensive census and insights into their behavior and orbital period variations.

Contribution

It presents the most complete catalog of superhumps in old novae and novalike variables using TESS data, including updated orbital ephemerides and period change analysis.

Findings

Identified superhumps in a large sample of old novae and novalike variables.

Compiled the most comprehensive census of superhumps in these stars.

Updated orbital periods and discussed period changes in eclipsing systems.

Abstract

Superhumps are among the abundant variable phenomena observed in the light curves of cataclysmic variables (CVs). They come in two flavours as positive and negative superhumps, distinguished by periods slightly longer or shorter, respectively, than the orbital periods of these interacting binary systems. Positive superhumps are ubiquitous in superoutbursting short period dwarf novae of the SU~UMa type but are less common in longer period systems with accretion disks in a permanent bright state such as novalike variables and most old novae. Negative superhumps do not seem not to have a preference for a particular type of CV. Here, I take advantage of the long high cadence light curves provided by TESS for huge number of stars, selecting all old novae and novalike variables with past reported superhumps for which TESS light curves are available and have not yet been analysed in previous publications in order to study their superhump behaviour. In combination with information taken from the literature the results enable to compile the most complete census of superhumps in these stars so far. As a corollary, for the eclipsing systems in the present sample of objects eclipse epochs derived from the TESS light curves and in some cases from archival light curves are listed and used to update orbital ephemeris and to discuss period changes.