Pretty Pleiades

1/7/07 – 1/13/07
by C. Zaitz

The Pleiades are so very pretty and interesting that they deserve some attention. You might know them as the Seven Sisters or might not know their name, but you’ve probably noticed them in the winter sky. They are often confused with the little dipper, but they are much tinier. In suburbia they are ephemeral, but if you are patient you can usually spot them in a cloudless sky. They are definitely worth knowing about, so let’s get to know them a little better.

The Pleiadian sisters are famous. Many cultures have seen and even worshipped the Pleiades, though they have been called many things in many languages. They rise in the east before Orion the Hunter, and he chases them across the sky all evening. The sister stars have even more mythological starry sisters, known as the Hyades. You may have noticed them as well, if you’ve seen the “v” shape of stars to the west of Orion. Look for Orion’s shiny belt of three stars and point up from there to find them. The “v” marks the face of Taurus, and the brightest star marks his eye. This star is named Aldebaran, which in Arabic means “the one who follows.” Aldebaran is not one of the Hyades, but the rest of the stars are. Some say the Seven Sisters are being chased by Orion, since the mighty hunter was notorious for having an eye for the ladies. If so, Orion will have to wait a very long time. The Pleiades are “running fast.”

Though they are often called “the Seven Sisters,” the faint group of stars is what we call an “open cluster” of many more than seven stars. Over 200 stars are collected in an area of space some 10-30 light years across. That is pretty dense compared to most of space, but open clusters are still less dense than the ancient globular clusters of stars we also find in the outskirts of galaxies. The Pleiades are known as the brightest open cluster of stars in the sky. Though they are not quite as pretty, the Hyades are much closer, “only” 130 light years away. The Pleiades are well over 400. If they were as close as the Hyades, imagine how spectacular they would be in our night sky!

The Pleiades were the daughters of Atlas, the man who was forced to carry the weight of the world on his shoulders, and Pleione, a sea nymph. The daughters all had beautiful Greek names: Maia, Electra, Taygete, Alcyone, Celaeno, Sterope, and Merope. Maia was the mother of Hermes by Zeus himself, and all the sisters except Merope consorted with gods. Merope was wooed by Orion and is said to have married Sisyphus. Since she was not of the immortal realm, her star faded. Some say that is why we can only make out six of the seven stars today.

Scientifically we know that the stars are receding from us, and eventually we may have difficulty in seeing any of the sisters with the naked eye, but until then, please enjoy them with binoculars, or just with your eyes. You can see the pretty stars all winter long.

Until next week, my friends, enjoy the view.