(PhysOrg.com) -- For almost two centuries, humans have looked up
at a bright star called Epsilon Aurigae and watched with their
own eyes as it seemed to disappear into the night sky, slowly
fading before coming back to life again. Today, as another
dimming of the system is underway, mysteries about the star
persist. Though astronomers know that Epsilon Aurigae is
eclipsed by a dark companion object every 27 years, the nature
of both the star and object has remained unclear. Now, new
observations from NASA's Spitzer Space Telescope -- in
combination with archived ultraviolet, visible and other
infrared data -- point to one of two competing theories, and a
likely solution to this age-old puzzle. 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 suppo