Jimmy Westlake: ‘Lyra and the Plunging Vulture’
June 1, 2008
What’s that bright star rising in the northeastern sky as darkness falls this month? It’s the star Vega, and its arrival is a sure sign that summer is just around the corner.
Vega is the brightest star in our constellation named Lyra, the Harp. The name Vega literally translates into “the plunging vulture,” so named because this bright star marks the head of a vulture holding the heavenly harp in his beak.
I’ve often wondered why Chevrolet wanted to name one of their cars after “the plunging vulture!” Lyra represents the harp made from an empty, magic tortoise shell by the famous mythological musician Orpheus.
In addition to the dazzling star Vega, this constellation includes a small parallelogram of four stars, dangling below Vega as it rises in the Northeast and representing the strings of the harp.
Lyra is a tiny, compact constellation and is easy to identify, primarily because of dazzling white Vega. Astronomers have determined that Vega rotates with its axis pointed almost directly at our sun, which means that our sun might be the pole star as seen from some Vegan planet, just as Polaris happens to be the north pole star for Earth. Ironically, Vega will be Earth’s pole star in about 10,000 years!
Brilliant Vega might be Lyra’s main claim to fame, but there are many others. The star marking the upper right corner in the parallelogram is an unusual double star named Sheliak.
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By chance alignment, once every 13 days, Sheliak’s fainter star eclipses its brighter star causing it to suddenly drop to one-half its normal brightness. Sheliak is one of the finest eclipsing binaries in the sky and its variations in light can be followed with the unaided eye.
Not far from Sheliak is the famous Ring Nebula, also known by its catalog number, M57. Often pictured in textbooks as the best example of a planetary nebula, the Ring Nebula was formed when a dying red giant star blew away its outer layers. The shell of gas continues to expand away from the star, forming what looks like a ghostly little smoke ring in the sky. A small telescope is required to spot the Ring Nebula, and its exact location can be found on any good star chart.
Beside Vega is the famous double-double star, Epsilon Lyrae. The two main components can be split with the unaided eye (if you have good eyesight!), but a telescope reveals that each of these is also double.
There’s a lot to see and enjoy in this tiny constellation of early summer, Lyra the Harp.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. He is an avid astronomer whose photographs and articles have been published on the Web sites of CNN.com, NASA’s “Astronomy Picture of the Day” Web site, Spaceweather.com, Space.com, Discover.com, MSNBC.com, NationalGeographic.com, and in Sky & Telescope, Astronomy, Night Sky, Discover, and WeatherWise magazines. His “Celestial News” article appears weekly in the Steamboat Pilot & Today. His “Cosmic Moment” radio spots can be heard on local radio station KFMU. Also, check out Jimmy’s Web site at http://www.jwestlake.com.