Observations of V592 Cassiopeiae with the Spitzer Space Telescope - Dust in the Mid-Infrared

TL;DR

This study presents mid-infrared observations of V592 Cassiopeiae, revealing a circumbinary dust disk that contributes to its spectral energy distribution, and discusses its potential origins and implications.

Contribution

First detection of a circumbinary dust disk in V592 Cassiopeiae using Spitzer mid-infrared data, linking dust presence to system winds and evolutionary history.

Findings

Circumbinary dust mass ~10^21 g.

Dust temperature peaks at ~500 K.

Dust likely replenished by stellar wind or remnant from formation.

Abstract

We present the ultraviolet-optical-infrared spectral energy distribution of the low inclination novalike cataclysmic variable V592 Cassiopeiae, including new mid-infrared observations from 3.5-24 microns obtained with the Spitzer Space Telescope. At wavelengths shortward of 8 microns, the spectral energy distribution of V592 Cas is dominated by the steady state accretion disk, but there is flux density in excess of the summed stellar components and accretion disk at longer wavelengths. Reproducing the observed spectral energy distribution from ultraviolet to mid-infrared wavelengths can be accomplished by including a circumbinary disk composed of cool dust, with a maximum inner edge temperature of ~500 K. The total mass of circumbinary dust in V592 Cas (~10^21 g) is similar to that found from recent studies of infrared excess in magnetic CVs, and is too small to have a significant effect on the long-term secular evolution of the cataclysmic variable. The existence of circumbinary dust in V592 Cas is possibly linked to the presence of a wind outflow in this system, which can provide the necessary raw materials to replenish the circumbinary disk on relatively short timescales, and/or could be a remnant from the common envelope phase early in the formation history of the system.