The Mid-Infrared Spectrum of the Short Orbital Period Polar EF Eridani from the Spitzer Space Telescope

TL;DR

This paper presents the first mid-infrared spectrum of the magnetic cataclysmic variable EF Eridani, revealing a flat continuum and suggesting dust emission dominates beyond 5 microns, with implications for circumbinary disk models.

Contribution

First mid-infrared spectrum of EF Eridani, combined with a spectral energy distribution model including dust, white dwarf, secondary star, and cyclotron emission, advancing understanding of its infrared properties.

Findings

Spectrum is featureless and flat from 5.5 to 14.5 microns.

Dust emission dominates the spectrum beyond 5 microns.

Cyclotron emission is not the main contributor at wavelengths >3 microns.

Abstract

We present the first mid-infrared (5.5-14.5 micron) spectrum of a highly magnetic cataclysmic variable, EF Eridani, obtained with the Infrared Spectrograph on the Spitzer Space Telescope. The spectrum displays a relatively flat, featureless continuum. A spectral energy distribution model consisting of a 9500 K white dwarf, L5 secondary star, cyclotron emission corresponding to a B~13 MG white dwarf magnetic field, and an optically thin circumbinary dust disk is in reasonable agreement with the extant 2MASS, IRAC, and IRS observations of EF Eri. Cyclotron emission is ruled out as a dominant contributor to the infrared flux density at wavelengths >3 microns. The spectral energy distribution longward of ~5 microns is dominated by dust emission. Even longer wavelength observations would test the model's prediction of a continuing gradual decline in the circumbinary disk-dominated region of the spectral energy distribution.