Fomalhaut
The Moon, a planet, and a bright star form a wide, skinny triangle tonight. As night falls, the planet Jupiter blazes far to the Moon's upper left. Jupiter far outshines all the true stars in the night sky, so you can't miss it. And well to the lower left of Jupiter, quite low in the southeast, is Fomalhaut, the brightest star of Piscis Austrinus, the southern fish. Although it's not nearly as bright as Jupiter, it stands out because there are no other bright stars around it.
Fomalhaut is about twice as big and massive as the Sun, and thousands of degrees hotter, so it shines pure white.
Fomalhaut is a stellar youngster. It's around 200 million years old -- less than one-twentieth the age of the Sun. And like many young stars, it's still swaddled in its baby blanket -- a disk of gas and dust that spans tens of billions of miles.
Much of this material consists of small bits of rock and ice -- the raw material for planets. Indeed, Earth and the other planets of our own solar system probably were born from just such a disk.
A few years back, astronomers discovered a big gap in this disk -- a gap that might be swept clear by the gravity of an orbiting planet. No one's found the planet yet -- but they have found one in a different orbit. Most of the planets in other star systems were discovered indirectly -- through their gravitational pull on their parent stars. But this planet has actually been seen. More about the planet tomorrow.
Script by Damond Benningfield, Copyright 2009
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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