Zubenelgenubi

StarDate: July 14, 2013

You are missing some Flash content that should appear here! Perhaps your browser cannot display it, or maybe it did not initialize correctly.

You are missing some Flash content that should appear here! Perhaps your browser cannot display it, or maybe it did not initialize correctly.



A scorpion’s claw consists of two parts, allowing the nasty little critter to grab its prey. And so it is in the sky, with the star that represents one of the claws of Scorpius. Zubenelgenubi, the southern claw, consists of two widely separated components, both of which are visible through binoculars.

Zubenelgenubi is actually a member of the constellation Libra, the balance scales. But Libra’s brightest stars have kept ancient names that refer to them as the claws of the scorpion, which is next door to Libra. The other is Zubeneschamali, the northern claw.

There’s more to Zubenelgenubi than even your binoculars can reveal. Each of the two visible stars is in fact a pair of stars on its own, for a total of four stars in all.

The stars in each pair are quite close together. But the two pairs are far apart — more than 5,000 times the distance from Earth to the Sun. At that range, it takes more than 2,000 centuries for the two pairs to complete a single orbit around each other.

There’s evidence that Zubenelgenubi has one more member — a star known as KU Librae. It’s three light-years away from the others, so it might not be bound to them. But it appears to be the same age and composition, it’s about the same distance from Earth, and it moves along with the others — perhaps extending the reach of the scorpion’s claw.

Look for Zubenelgenubi in the south as night falls, to the upper right of orange Antares, the bright heart of the scorpion.

 

Script by Damond Benningfield, Copyright 2013

For more skywatching tips, astronomy news, and much more, read StarDate magazine.

The one constant in the Universe: StarDate magazine

FacebookTwitterYouTube

©2014 The University of Texas McDonald Observatory