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Link: http://dsc.discovery.com/news/2007/0...19-502-ak-0000
April 24, 2007 — Astronomers have found the first Earth-sized world circling its mother star at a distance suitable for life. It also has good prospects for liquid surface water — believed to be a key ingredient for life.
"This planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life," said Xavier Delfosse, with Grenoble University in France.
It will be years before more sensitive instruments are developed to glean additional clues about whether life exists on the planet.
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"It is not possible with current telescopes and instruments yet," Xavier Bonfils, an astronomer with the Lisbonne Observatory in Portugal, wrote in an e-mail to Discovery News. "But in the next decade, we may have the tools to answer this question."
The planet, which is about 50 percent larger than Earth, circles a star in the constellation Libra known as Gliese 581, about 20.5 light-years away. Light travels in a vacuum at about 187,000 miles per second.
Astronomers previously have found a Neptune-sized world circling Gliese 581, as well as strong evidence for a third planet about eight times the mass of Earth.
The new planet, which is the smallest planet beyond our solar system found to date, circles its star 14 times closer than Earth orbits the sun. But because Gliese 581 is smaller and colder than our sun, the system's so-called habitability zone, where liquid water and thus life is possible, is closer to the mother star than in our solar system.
Astronomers estimate the mean temperature of the newly discovered planet to be between 0 degrees and 104 degrees Fahrenheit.
"Water would be liquid," notes lead researcher Stephane Udry with Switzerland's Geneva Observatory. "Models predict that the planet should be either rocky — like our Earth — or covered with oceans."
The discovery likely will bolster efforts to find other Earth-like planets circling so-called red dwarf stars, which are the most common type of stars in our galaxy. Of the 100 closest stars to the sun, 80 are red dwarfs.
"Red dwarfs are ideal targets for the search for such planets because they emit less light, and the habitable zone is thus much closer to them than it is around the sun," Bonfils said.
Planets closer to their mother stars are typically easier to find than those farther away. The scientists, part of an international team from Switzerland, France and Portugal, submitted their findings for publication in the journal Astronomy and Astrophysics.
The discovery was made using with the Chile-based European Southern Observatory High Accuracy Radial Velocity for Planetary Searcher instrument.
Interesting stuff.
April 24, 2007 — Astronomers have found the first Earth-sized world circling its mother star at a distance suitable for life. It also has good prospects for liquid surface water — believed to be a key ingredient for life.
"This planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life," said Xavier Delfosse, with Grenoble University in France.
It will be years before more sensitive instruments are developed to glean additional clues about whether life exists on the planet.
advertisement
line
"It is not possible with current telescopes and instruments yet," Xavier Bonfils, an astronomer with the Lisbonne Observatory in Portugal, wrote in an e-mail to Discovery News. "But in the next decade, we may have the tools to answer this question."
The planet, which is about 50 percent larger than Earth, circles a star in the constellation Libra known as Gliese 581, about 20.5 light-years away. Light travels in a vacuum at about 187,000 miles per second.
Astronomers previously have found a Neptune-sized world circling Gliese 581, as well as strong evidence for a third planet about eight times the mass of Earth.
The new planet, which is the smallest planet beyond our solar system found to date, circles its star 14 times closer than Earth orbits the sun. But because Gliese 581 is smaller and colder than our sun, the system's so-called habitability zone, where liquid water and thus life is possible, is closer to the mother star than in our solar system.
Astronomers estimate the mean temperature of the newly discovered planet to be between 0 degrees and 104 degrees Fahrenheit.
"Water would be liquid," notes lead researcher Stephane Udry with Switzerland's Geneva Observatory. "Models predict that the planet should be either rocky — like our Earth — or covered with oceans."
The discovery likely will bolster efforts to find other Earth-like planets circling so-called red dwarf stars, which are the most common type of stars in our galaxy. Of the 100 closest stars to the sun, 80 are red dwarfs.
"Red dwarfs are ideal targets for the search for such planets because they emit less light, and the habitable zone is thus much closer to them than it is around the sun," Bonfils said.
Planets closer to their mother stars are typically easier to find than those farther away. The scientists, part of an international team from Switzerland, France and Portugal, submitted their findings for publication in the journal Astronomy and Astrophysics.
The discovery was made using with the Chile-based European Southern Observatory High Accuracy Radial Velocity for Planetary Searcher instrument.
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