Archive for the extra-solar planet Category

6 New Super Earths Discovered!

Posted in Exoplanet, extra-solar planet with tags , , , on December 17, 2009 by Rick Buggy's Rants & Ravings

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The race to find Earth-like planets around stars similar to our sun edged closer to a finish with the announcement on Monday that up to six “super-Earths” have been found orbiting sun-like neighbor stars.Astronomers have found up to six new planets orbiting stars that resemble the sun, paving the way forward for the discovery of a truly extraterrestrial Earth. NASA

The smallest of the bunch weighs in at about five times the mass of Earth and orbits a star known as 61 Virginis, which is visible with the naked eye in the constellation Virgo. The star is 28 light-years from Earth and closely resembles the sun in size, age and other attributes.

Two other newly detected planets — each about the size of Neptune — are part of 61 Virginis’ family.

Another planet that is 7.8 times larger than Earth orbits HD 1461, a sun-like star located 76 light-years away in the constellation Cetus. Two sibling planets may orbit this same star, though confirmation is still pending, astronomer Gregory Laughlin, with the University of California’s Lick Observatory, told Discovery News.

“I think this is really the tip of the iceberg” Laughlin said. “There’s so many planets that have been detected now; it’s completely clear that planets aren’t rare. With our program, we’ve been focusing very intently on finding low-mass planets that orbit very nearby solar-type stars.”

An international team of researchers detected the new planetary systems by combining information collected during years of observations at the Keck Observatory in Hawaii and the Anglo-Australian Telescope in Australia.

The astronomers combed the data looking for minute variations in the starlight caused by gravitational tugs of orbiting planets.

“This was not the kind of ‘ah-ha’ moment where you look into the telescope and see the planet sitting there,” Laughlin said. “The signal builds up over time.”

Refinements in planet-hunting techniques should make detection of Earth-sized planets possible in about a year, he added.

“The practical limits for finding terrestrial planets around nearby stars is a lot more optimistic than what was thought to be the case a few years ago,” Laughlin said.

The newly discovered planets are too close to their parent stars for liquid water to exist on their surfaces, a condition that is believed to be necessary for life. Still, scientists say the discoveries, announced in this week’s Astrophysical Journal, are paving the way toward finding the first true extraterrestrial Earth.

“We are knocking on the door right now of being able to find habitable planets,” said Paul Butler, with the Carnegie Institution.

In other news, a “super-Earth” has been discovered orbiting a red dwarf star on our cosmic doorstep, only 42 light years away. But here’s the best bit: it’s composed primarily of water, possibly in liquid form.

A “super-Earth” is an exoplanet (or “extra-solar planet”) with a mass of 5-10 Earths. Only one other super-Earth has been confirmed (and a few more candidates have just been announced), the other 400 exoplanets we know of are many times bigger and are often referred to as “hot Jupiters” (many orbit very close to their host stars, getting roasted).

In this case, the exoplanet called GJ 1214b is 6.5 times the mass and 2.7 times wider than our planet, so it is certainly closer to our planet’s characteristics. As a comparison, this world is a celestial body somewhere between the mass of Earth and Uranus.

Although this is exciting news, even more impressive is the fact that astronomers have worked out that its density is low enough to contain large quantities of water. As the exoplanet is so close (in astronomical scales) we should soon be able to analyze its atmosphere to confirm the presence of this water.

Although this particular waterworld might not be suitable for habitation, the researchers who made this discovery think we’re on the right track.

“These planets are like mileposts on the road rather than a destination itself,” said Greg Laughlin of the University of California, Santa Cruz, a coauthor of the paper published in the Dec. 17 edition of the journalNature. “It’s very exciting to know that we’re getting close.”

Original posts on Discovery News

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