“2010: The Year of the Baffling Eclipse”(PDF)
 

Epsilon Aurigae is eclipsed by a dark companion object every 27 years, the nature of both the star and object has remained unclear.
One theory holds that the bright star is a massive supergiant, periodically eclipsed by two tight-knit stars inside a swirling, dusty disk. The second theory holds that the bright star is in fact a dying star with a lot less mass, periodically eclipsed by just a single star inside a disk. The Spitzer data strongly support the latter scenario.
PDF>http://www.citizensky.org/sites/defa...10-printed.pdf