Tidal Instability and Superhump by a Wave-Wave Resonant Model

TL;DR

This paper investigates whether a wave-wave resonant interaction in deformed accretion disks can explain tidal instability and superhumps in dwarf novae, suggesting a potential common mechanism with high-frequency QPOs in X-ray binaries.

Contribution

It proposes a wave-wave resonant model to explain tidal instability and superhumps, linking these phenomena to resonant oscillations in deformed accretion disks.

Findings

The resonant process can describe observed tidal instability and superhumps.

A two-armed high-frequency oscillation is expected in disks.

The amplitude of this oscillation may be small.

Abstract

On a disk deformed to a non-axisymmetric form, a set of oscillations can be excited by their resonant interaction through the disk deformation (Kato et al. 2011). This resonant instability process has been proposed to suggest a possible cause of the high-frequency quasi-periodic oscillations (HF QPOs) observed in black-hole low-mass X-ray binaries. In the present paper, we examine whether the above-mentioned wave-wave resonant process can describe the tidal instability and superhump in dwarf novae. The results show that the process seems to well describe the observations. If this process is really the cause of the tidal instability and superhump, a two-armed oscillation with high frequency roughly on the magnitude of three times the orbital frequency is present on disks, although its expected amplitude may be small.