ExtraSolarPlanet_04-21-2010 - Exoplanets and the search for...

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Exoplanets and the search for life Introduction An extrasolar planet, or exoplanet, is a planet beyond the Solar System, orbiting around another star. As of January 2009, 335 extra solar planets have been discovered. Most are massive gas giant planets resembling our own Jupiter, but it is believed that with advances in technological techniques, small rocky planets (e.g., Earth, Mars etc) will eventually outnumber extrasolar gas giants found. The existence of extrasolar planets has been inferred since the mid-19th century. Many astronomers surmised that such planets existed, but they had no way of knowing how common they were or how similar they might be to the planets of the Solar System. The vast majority have been detected through radial velocity observations and other indirect methods rather than actual imaging. The first confirmed radial velocity detection was made in 1995, revealing a gas giant planet in a four day orbit around the nearby G type star, 51 Pegasi. Now, it is estimated that at least 10% of sun-like stars have planets, but the true proportion may be much higher. The discovery of extrasolar planets sharpens the question of whether some might support extraterrestrial life. You have already looked at the Drake equation in the pre-lab exercise. While it can be enjoyable to think about whether or not there is intelligent life in the Milky Way, so far astronomers have not discovered signs of life anywhere but on Earth. There is a lot of territory to search though and it would be good to limit the search to likely places for life. The lab exercises below will help you get a feel for planetary systems found to date, and some things to consider when looking for possible planets that might harbor life. I. Finding Exoplanets
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This note was uploaded on 02/06/2011 for the course ASTR 114 taught by Professor Staff during the Spring '08 term at George Mason.

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ExtraSolarPlanet_04-21-2010 - Exoplanets and the search for...

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