Planetary Transit
The unicorn tags along behind the hunter tonight. It's not much to look at, but it was the site of a neat discovery earlier this year: a planet orbiting another star. Most important, it could be the first of hundreds of new planets to be discovered with the same technique in the next few years.
The unicorn is the constellation Monoceros. It rises below Orion, the hunter, and clears the horizon by about 10 o'clock.
About six months ago, scientists reported that a European spacecraft named COROT had discovered a planet there. It found the planet as it passed in front of its parent star -- an event known as a transit. The planet blocked a bit of the star's light, so the star grew fainter.
The change wasn't much, but it was enough for scientists to learn that the planet's bigger and more massive than Jupiter, the largest planet in our own solar system. And it orbits its star once every day and a half.
Scientists expect to find more planets in COROT's observations of thousands of stars. And a NASA mission could find hundreds of planets using the same technique. The Kepler mission will use a bigger telescope than COROT, and operate longer. It may find planets as small as Earth, and even reveal some details about them.
More about transits tomorrow.
Look for Orion's Belt -- a line of three stars standing almost straight up in the east -- in mid evening. Monoceros is below the Belt in the evening, and trails to the side of Orion as it wheels across the south during the night.
Script by Damond Benningfield, Copyright 2007
For more about the Kepler Mission, visit NASA's website at http://kepler.nasa.gov.
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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