Ten More Planets Discovered – Total Now Over 50
From Stig Agermose: By Dan Vergano – USA TODAY
Astronomers plan Monday to announce the discovery of 10 new planets orbiting nearby stars, bringing the total to more than 50 discovered since 1995.
Further, researchers say the planets, which include both the smallest and the closest to our solar system yet detected, point to a starry neighbourhood near-Earth crowded with multiple planetary systems like our own. “The observations suggest stars often form complete hosts of planetary systems, says astronomer Debra Fischer of the University of California, Berkeley, a member of one of four teams announcing planet detections at the International Astronomical Union meeting in the United Kingdom. Mostly, the newly detected planets resemble many of those discovered already by astronomers – large gas giant planets close to Jupiter in size, but following elongated, or eccentric, orbits around stars within 200 light-years of Earth. (One light-year equal 5.878 trillion miles.) Such massive objects reveal themselves by the “wobble their gravitational pull, akin to the Moon’s tidal effects on Earth’s oceans, causes their host star. However, both a Swiss team and Fischer’s group report finding second planets in stars already known to harbour a gas giant, at stars HD 83443 and HD 38529 (in the Orion constellation) respectively. A multiple-planet system was reported at the star Upsilon Andromedae in last year, but until now astronomers had been hesitant to describe solar systems as commonplace. “We have several other (planet) candidates that show a drift indicating there is something else in their system, says astronomer Stephane. Udry. of the Geneva Observatory, a member of the Swiss team. Fischer plans today to discuss an analysis suggesting that of 12 planet-harbouring stars her team has observed for more than two years, five show signs of further companions. “Planets are bursting out all over, says astronomer Stephen Maran. of the American Astronomical Society. He expects more finds in coming years, as astronomers look at more nearby stars for long periods of time. One of the newly discovered planets, the second one discovered orbiting the star HD 83443, represents the smallest planet yet detected. It’s still large ” over 45 times bigger than Earth ” but less than half the size of Saturn. A team led by William Cochrane. of the University of Texas in Austin. will announce the discovery of the closest planet yet detected, circling the star Epsilon Eridani, only 10.5 light-years from Earth. The star was one of the first that the founder of the Search for Extraterrestrial Intelligence (SETI) project started looking at three decades ago. (Fans of TV’s Star Trek know the Epsilon Eridani as a possible home of the planet Vulcan, where Mr Spock originated.) Finding a planet a mere 10 light-years away is like finding an alligator in my back yard, says Seth Shostack of the SETI Institute in Mountain View, Calif. “It tells me that alligators must be a dime a dozen. They must be everywhere, he says.