New Star Found in Big Dipper

[mickw]

One of the stars that makes the bend in the ladle's handle, Alcor, has a smaller red dwarf companion, new observations have revealed.
Alcor is a relatively young star twice the mass of the Sun. Stars this massive are relatively rare (less than a few percent of all stars), short-lived, and bright.

Alcor and its cousins in the Big Dipper formed from the same cloud of matter about 500 million years ago, something unusual for a constellation since most of these patterns in the sky are composed of unrelated stars.

Alcor looks to be in the same position in the Big Dipper with another star, Mizar from the perspective of a viewer on Earth. In fact, both stars were used as a common test of eyesight — being able to distinguish "the rider from the horse" (as the two stars are unofficially known) — for ancient Arab, Roman and English warriors. (Mizar is the brighter of the two stars and can still be seen with the naked eye, while Alcor, a little fainter, would take relatively dark skies to see.)

More:   http://www.space.com/scienceastronomy/091209-big-dipper-new-star.html

[Rick]

Stargazers at the US's University of Rochester have announced that Mizar in the asterism of the Plough (the Big Dipper to our US cousins) is actually a six-star system.

Mizar was scientifically confirmed as the first known binary star system back in 1617, by Benedetto Castelli and Galileo, who demonstrated that Mizar was linked to Alcor

More: http://www.theregister.co.uk/2009/12/14/alcor_b/