Sunday, November 26, 2006
Shining brightly in the southern sky as darkness falls is one of autumn's few bright stars, a blue gem named Fomalhaut (pronounced foam-a-low). Fomalhaut belongs to our constellation of Piscis Austrinus, the Southern Fish, pictured on ancient star atlases as swimming belly-up and swallowing the stream of water flowing from the water jug of Aquarius hovering above. In fact, the name Fomalhaut comes from the Arabic words meaning "the mouth of the fish."
Fomalhaut was considered one of the four royal stars in ancient Mesopotamia, along with Regulus, Aldebaran, and Antares. Its appearance signaled the arrival of the season of fall. More recently, Fomalhaut has served as an important navigational beacon because of its far southerly position. In fact, from Colorado, Fomalhaut is the most southerly first magnitude star visible.
The light that you see coming from Fomalhaut tonight actually left the star 25 years ago in 1981 and is just now arriving. In 1983, NASA's IRAS satellite discovered a flattened disk of dusty debris spinning around this star. It is thought that the planets in our own solar system, including Earth, formed within just such a spinning cloud of dust around the young Sun. Could Fomalhaut be in the process of building its own planetary system?
This wouldn't surprise astronomers at all. In the past decade, more than 200 planets have been discovered orbiting other stars in our galaxy. For the time being, at least, no full-blown planets are known to circle Fomalhaut.
To find Fomalhaut, look due south around 7:00 PM in late November, about a hand-span above the horizon. It's easy to locate in the southern sky because there are no other stars of comparable brightness nearby. So, next time you're outside in the early evening, glance to the south and see if you can spot the "Mouth of the South," the star Fomalhaut.
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," Spaceweather.com, Space.com, Discover.com, and in Sky & Telescope, Astronomy, Night Sky, Discover, and WeatherWise magazines.