Astronomers spot three earth-like planets
17 Dec 2009
Astronomers working at the Harvard-Smithsonian Centre for Astrophysics (CfA) announced that they found a 'super Earth' 40 light-years from our planet using ground-based telescopes such as those used by amateur astronomers. The other two 'super earths' were discovered by a team led by Steven Vogt of the University of California, Santa Cruz, and Paul Butler of the Carnegie Institution of Washington.
One of the 'super earths', named GJ1214b, orbits the red star GJ1214, which is about one-fifth the size of the Sun. About 6.5 times as massive as the Earth, the planet's density suggests that it is composed of about three-fourths water and other ices, and one-fourth rock. The surface temperature of about 4,900 degrees Fahrenheit makes the planet too hot to support life; even extremophiles that survive high temperatures in geysers and deep, super-hot mines cannot hope to survive here. However, it is still cooler than any other known transiting planet.
"Despite its hot temperature, this appears to be a waterworld," said Zachory Berta, a graduate student at CfA, who first spotted the hint of the planet among the data. Some of the planet's water could be in a crystalline form, Ice VII - water that exists at pressures greater than 20,000 times Earth's atmosphere. There are also indications that the planet has a gaseous atmosphere.
An American-Australian team takes credit for the discovery of the other two 'super earths', which are mentioned in articles to be published in the Astrophysical Journal. The team has discovered as many as six low-mass planets around two nearby Sun-like stars, including the two 'super earths'. Combined data from the WM Keck Observatory in Hawaii and the Anglo-Australian Telescope in New South Wales, Australia, yielded information about the planets.
"These detections indicate that low-mass planets are quite common around nearby stars. The discovery of potentially habitable nearby worlds may be just a few years away," said Vogt, a professor of astronomy and astrophysics at UCSC.
The new planets were found orbiting the stars 61 Virginis and HD 1461. Only 28 light-years away, 61 Virginis has fascinated astronomers by being nearly similar to the Sun in terms of age, mass, and other essential properties. Another near-perfect twin of the Sun, HD 1461, located 76 light-years away, hosts the other 'super Earth'. The planets have been named 61Virb and HD1461b, and have masses 5 and 7.5 times the mass of the Earth.
