TESS light curves of cataclysmic variables -- III -- More superhump systems among old novae and novalike variables

TL;DR

This study analyzes TESS light curves of 23 novalike variables and old novae, revealing superhumps in all and identifying 19 with first-time detections, thus significantly expanding the known population and updating related relations.

Contribution

It presents new superhump detections in 19 systems, updates the census of superhump stars, and refines orbital period measurements, enhancing understanding of cataclysmic variables.

Findings

Superhumps detected in all 23 studied systems.

19 systems exhibit first-time superhump detections.

Updated the Stolz-Schoembs relation and improved orbital period data.

Abstract

Continuing previous work on the identification and characterization of periodic and non-periodic variations in long and almost uninterrupted high cadence light curves of cataclysmic variables observed by the TESS mission, the results on 23 novalike variables and old novae out of sample of 127 suchsystems taken from the Ritter & Kolb catalogue are presented. All of them exhibit at least at some epochs either positive or negative (or both) superhumps, and in 19 of them superhumps were detected for the first time. The basic properties of the superhumps such as their periods, their appearance and disappearance, and their waveforms are explored. Together with recent reports in the literature, this elevates the number of known novalike variables and old novae with superhumps by more than 50%. The previous census of superhumps and the Stolz-Schoembs relation for these stars are updated. Attention is drawn to superhump properties in some stars which behave differently from the average, as well as to positive superhumps in high mass ratio systems which defy theory. As a byproduct, the orbital periods of 13 stars are either improved or newly measured, correcting previously reported erroneous values.