Eclipsing binary stars. Illustration depicting the two stars of the Epsilon Aurigae eclipsing binary system. Epsilon Aurigae is a spectral class F supergiant star. Its brightness varies with a period of about 27 years. This is best explained by it having a small, massive binary companion (below centre) which is surrounded by a disk of dust and gas. The light from Epsilon Aurigae is partly eclipsed by the disk as it passes between the main star and observers on Earth. Epsilon Aurigae is about 2000 light years away in the constellation Auriga, and was known to ancient astronomers as Al Anz.