Accretion Disks in Evolved Cataclysmic Variables

TL;DR

This paper investigates the structure and behavior of accretion disks in evolved short-period cataclysmic variables, highlighting the role of spiral arms and resonance effects in their observational features.

Contribution

It models accretion disks in evolved CVs with extreme mass ratios, emphasizing the impact of spiral arms and resonances on disk structure and light curves.

Findings

Disks grow to the size of the Roche lobe in systems with extreme mass ratios.

Spiral arms formed by 2:1 resonance have higher viscosity and temperature.

Modeled light curves match observed double-humped features in several CVs.

Abstract

We explore conditions and structure of accretion disks in short-period Cata- clysmic Variables (CVs), which have evolved beyond the period minimum. We show that accretion discs in systems with extreme mass ratios grow up to the size of corresponding Roche lobe and are relatively cool. In contrast, the viscosity and temperature in spiral arms formed as a result of a 2:1 resonance are higher and their contribution plays an increasingly important role. We model such discs and generate light curves which successfully simulate the observed double-humped light curves of SDSS1238, SDSS0804, SDSS1610 and V 455 And in quiescence.