A star with a dual identity butts heads with the Moon this evening. Officially, the star is in the constellation Taurus, the bull. But it also forms part of the pattern of Auriga, the charioteer.
The star is El Nath -- an Arabic name that means "the butting one" -- a reference to its location at the tip of one of the bull's horns.
Until three-quarters of a century ago, there were no rules for what stars belonged to which constellations. Some stars were placed in more than one constellation, while others had no constellation at all. So El Nath formed part of the classical five-star pattern that outlines the charioteer, while also representing the bull's horn.
But in 1930, astronomers divided the sky into 88 constellations, with precise borders for all of them. El Nath fell just inside Taurus.
The star itself is big, hot, bright, and late in life. It may soon puff up to form a red giant -- a star that's dozens of times the Sun's diameter.
It's close to a point in space that marks the opposite direction from the center of the Milky Way galaxy. So when we look at El Nath, we're looking away from the crowded inner portion of the galaxy, and toward its less-populated rim -- and intergalactic space beyond.
Look for El Nath a little above the Moon at nightfall. The Moon will move even closer to the star later on. In fact, from the West Coast, Alaska, and Hawaii, they'll almost appear to touch -- a bright star butting heads with the Moon.
Script by Damond Benningfield, Copyright 2005, 2008
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
[1]
