Modeling the Multi-Wavelength Light Curves of EF Eridanus:
The Detection of its Irradiated Brown Dwarf-like Secondary Star

Tom Harrison

We have obtained simultaneous optical and infrared photometry of the ultra-short period magnetic cataclysmic variable EF Eridanus. The optical data (from the NMSU 1m) were easily modeled with a hot spot (the magnetic pole accretion region) on the surface of a 9,500 K white dwarf. The infrared data, however, were quite unusual. The J-band light curve was superficially similar to the optical data, but indicated the presence of an additional source of luminosity. We propose that cyclotron emission from residual mass accretion in the 15 MG magnetic field is responsible. The H- and K-band light curves were remarkable: in the K-band the peak-to-peak amplitude of the variations is 0.8 mag. We were able to model the H- and K-band light curves using a model where a 900K brown dwarf-like object is being heated by the white dwarf primary. I will present new K-band spectra obtained with Gemini to identify additional peculiarities of EF Eridanus.