A systematic study of spiral density waves in the accretion discs of Cataclysmic Variables

TL;DR

This study systematically searched for spiral density waves in cataclysmic variable stars' accretion discs, detecting them in two out of sixteen systems, and found that system inclination influences their observability.

Contribution

It provides the first systematic observational survey for spiral density waves in CVs and highlights the role of system inclination in their detection.

Findings

Spiral density waves detected in 2 of 16 CV systems.

Most systems show asymmetric, non-Keplerian discs during outburst.

Inclination angle affects the visibility of spiral waves.

Abstract

Spiral density waves are thought to be excited in the accretion discs of accreting compact objects, including Cataclysmic Variable stars (CVs). Observational evidence has been obtained for a handful of systems in outburst over the last two decades. We present the results of a systematic study searching for spiral density waves in CVs, and report their detection in two of the sixteen observed systems. While most of the systems observed present asymmetric, non-Keplerian accretion discs during outburst, the presence of ordered structures interpreted as spiral density waves is not as ubiquitous as previously anticipated. From a comparison of systems by their system parameters it appears that inclination of the systems may play a major role, favouring the visibility and/or detection of spiral waves in systems seen at high inclination.