Orion's Head

StarDate: March 17, 2010

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When spring arrives on Saturday, the Sun will stand near the body of one of the fish of Pisces. Over time, though, the Sun's location at the vernal equinox slips westward. About 6500 years ago, the point of the vernal equinox was just above the head of Orion, the hunter.

Orion is best known for his strong shoulders and legs and his sparkling belt. The tiny triangle of stars that marks his head doesn't look nearly as impressive. Yet the stars themselves really are standouts.

The brightest of the three is known as Lambda Orionis. It's actually a pair of stars locked in a tight orbit. Both stars are many times bigger, hotter, and brighter than the Sun. In fact, one of them is a member of the hottest class of stars. It's tens of thousands of degrees hotter than the Sun, and more than 60,000 times brighter. That makes it easily visible across more than a thousand light-years of space.

The other stars are Phi-1 and Phi-2 Orionis, which represent the hunter's cheeks. Although they share a name, they aren't related -- they're hundreds of light years apart. But both are much more impressive than the Sun -- big stars for a prominent constellation.

Orion is in the southwest at nightfall. Look for his Belt -- a short line of three bright stars -- lining up parallel to the horizon, with the bright orange star Betelgeuse above it. The faint triangle that makes up Orion's head is to the right of Betelgeuse.

Script by Damond Benningfield, Copyright 2010

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