What are the Pleiades, and where can we see them?
The Pleiades is a beautiful cluster of stars, which can be seen with the naked eye (meaning you don't need binoculars or a telescope to see this cluster). The unaided eye can see about seven stars in this cluster, which is sometimes called the Seven Sisters (based upon ancient Greek mythology). In actuality, there are thousands of stars in this famous cluster, including cool faint brown dwarf stars. The Pleiades cluster is an "open" (or "galactic") cluster of stars about 400 light years from Earth. Open clusters are loosely bound together by gravitation, and usually contain young, bright stars. The stars in the Pleiades are encased in a ghostly reflection nebula, which can be seen through a telescope. A reflection nebula is caused by starlight scattering off dust particles. This nebula appears blue, because blue light is scattered more efficiently than red light.
Drawing of Orion and Taurus constellations
The Pleiades are found in the constellation Taurus, riding on the "back" of the bull. Taurus is located near the famous Orion constellation, and is visible from 90 degrees north latitude to 65 degrees south latitude. Follow Orion's belt in the direction opposite of Sirius, and you'll find the V-shaped head of Taurus. Right now, in the northern hemisphere, Taurus is high in the east around 9pm. By mid-January, Taurus and the Pleiades will be high in the southern sky around 9pm. From the southern hemisphere, look toward the north to find Taurus.
Taurus
is also home to another open cluster of stars - the Hyades. The Hyades
marks the head of Taurus. The bright reddish star, Aldebaran, is also
visible at the head of Taurus, but is not a part of the Hyades cluster.
For
more information on the Pleiades and well as telescope views, see:
http://www.seds.org/messier/m/m045.html
Dr. Beth Brown is an astrophysicist in the National Space Science Data Center at NASA Goddard Space Flight Center. She is involved with data acquisition and archiving, and her research focuses on the x-ray emission from elliptical galaxies.