Quiescent Superhumps Detected in the Dwarf Nova V344 Lyrae by Kepler

TL;DR

This study uses high-precision Kepler data to detect quiescent superhumps in the dwarf nova V344 Lyrae, revealing persistent accretion disk oscillations during different outburst states and providing insights into disk dynamics and binary parameters.

Contribution

First detection of quiescent superhumps in V344 Lyrae using Kepler, demonstrating continuous disk oscillations across outburst states and refining understanding of accretion disk behavior.

Findings

Superhumps persist during quiescence and normal outbursts.

Disk radius varies less than 2% during superhumping.

Possible identification of negative superhump indicating a tilted, retrograde-precessing disk.

Abstract

The timing capabilities and sensitivity of Kepler, NASA's observatory to find Earth-sized planets within the habitable zone of stars, are well matched to the timescales and amplitudes of accretion disk variability in cataclysmic variables. This instrumental combination provides an unprecedented opportunity to test and refine stellar accretion paradigms with high-precision, uniform data, containing none of the diurnal or season gaps that limit ground-based observations. We present a 3-month, 1 minute cadence Kepler light curve of V344 Lyr, a faint, little-studied dwarf nova within the Kepler field. The light curve samples V344 Lyr during five full normal outbursts and one superoutburst. Surprisingly, the superhumps found during superoutburst continue to be detected during the following quiescent state and normal outburst. The fractional excess of superhump period over the presumed orbital period suggests a relatively high binary mass ratio in a system where the radius of the accretion disk must vary by less than 2% in order to maintain tidal precession throughout the extended episode of superhumping. Disk radius is less restricted if the quiescent signal identified tentatively as the orbital period is a negative superhump, generated by a retrograde-precessing accretion disk, tilted with respect to the binary orbital plane.