What makes the luminous star known as Object X look so dim?
One might think that it would be hard to hide a star some 500,000 times more radiant than the sun, but distance and dust seem to have conspired to do just that. A group of astronomers has identified such a star in the Triangulum Galaxy, a neighbour to our own Milky Way Galaxy about three million light-years away. The star is barely detectable in visible light, but it shines brightly in the mid-infrared bands accessible to NASA's Spitzer Space Telescope. In fact, it is the brightest mid-infrared object in the entire galaxy, a fact that seems to have escaped notice until researchers from Ohio State University and the National Observatory of Athens in Greece went digging through the Spitzer data. The team weighs in on what would cause a star to look so strange in a study in the May 1 issue of The Astrophysical Journal. Read more