The Epsilon Aurigae secondary - A binary embedded within a disk?

Abstract

The eclipse characteristics of Epsilon Aurigae, which is an F supergiant in a spectroscopic binary system, imply a secondary that is elongated, measuring about 10 AU by less than 1 AU, with a mass of about 16 solar masses. Recent IR observations, however, indicate a color temperature of about 500 K and a luminosity that is apparently less than 1 percent that of a 16-solar mass star. It is presently suggested that the secondary consists of a close binary embedded in an optically thick disk, which is viewed edge-on. The observed low luminosity of the secondary would then be due to two 8-solar mass stars' luminosity, which is about 10 percent that of a 16-solar mass star, together with the loss of 90 percent of the emitted energy through escape from the poles of the disk. This hypothesis is discussed in relation to radio and UV observations of Epsilon Aurigae.