'Mysterious' dark object observed
Published 08/04/2010 | 07:51
A "mysterious dark companion" has been observed for the first time in a star system which has puzzled sky-watchers since the 19th century.
Scientists have taken close-up pictures of Epsilon Aurigae during its eclipse, which happens every 27 years.
Using an instrument developed at the University of Michigan in the US, astronomers were able to zoom in on the star, which is likely to be about 2000 light years away from our solar system.
This enabled them to identify the shape of a dark object's shadow.
For more than 175 years, astronomers have known that Epsilon Aurigae - the fifth brightest star in the northern constellation Auriga - is dimmer than it should be, given its mass.
They noticed its brightness dip for more than a year every few decades and surmised that it was part of a binary system consisting of two objects, where one was invisible.
The second object - the "companion" - was assumed to be a smaller star, orbited by a thick disk of dust.
The new images support this theory, showing a geometrically thin, dark, dense but partially translucent cloud passing in front of Epsilon Aurigae.