On the superhumps and mass ratio of CzeV404

TL;DR

This paper revises the mass ratio of the dwarf nova CzeV404, resolving previous discrepancies and clarifying its classification and relation to other cataclysmic variables.

Contribution

It identifies errors in earlier superhump-based mass ratio estimates and provides a new, consistent value based on updated analysis.

Findings

Revised mass ratio q=0.247(5) for CzeV404

Clarifies that CzeV404 is not an unusual dwarf nova

Disputes the link between SW Sex and SU UMa systems

Abstract

CzeV404 is an SU UMa-type dwarf nova in the period gap. Kara et al. (2021) (arXiv:2107.02664) recently published photometric and spectroscopic observations and obtained a mass ratio q=0.16, which is in severe disagreement of q~0.32 estimated from superhump observations (Bakowska et al., 2014). I here present what analysis was wrong or outdated in Bakowska et al. (2014) and provide a new value of q=0.247(5), consistent with the known behavior of superhumps and the evolution of cataclysmic variables. CzeV404 does not look like an unusual dwarf nova as suggested by Kara et al. (2021) and I discuss that the link between SW Sex and SU UMa systems suggested by Kara et al. (2021) is not supported.