By Deborah Byrd
Earth Sky Communications

Thursday July 2, 2009

Tonight’s moon appears near the upper part of the constellation Scorpius. These three stars are sometimes called the Crown of the Scorpion. The Crown stars are Graffias, Dschubba and Pi Scorpii.

Scorpius — which is now found in the south-southeastern sky at nightfall — is the constellation of the Scorpion. Later on in the evening, the mood and the Scorpion will shift into the southern sky.

It’s rare when our sky’s dome have anything to do with real associations of stars in space, but Graffias, Dschubba and Pi Scorpii are thought to be loosely bound by gravity. All three are located at approximately light-years away. All are thought to be members of the Scorpio-Centaurus group, which was first recognized by astronomers in the early part of this century.
   
About 100 stars are known in the Scorpio-Centaurs’ group, including Antares, the brightest star in Scorpius — also pictured on today’s chart. For more about Antares, see Saturday’s chart. The Scorpio-Centaurs’ stars share a common motion through space. They were probably all born from a single vast cloud of gas and dust. In other words, these stars are much like a family — loosely bound — sharing a common history.

More online at www.EarthSky.org.