Scientists are close to announcing the first Earth-sized planet in a habitable zone around its parent star.
Astronomer Thomas Barclay, with NASA's Ames Research Center in California, culled data collected by the Kepler space telescope to ferret out a five-planet system, the outermost of which circles toward the outer edge of its star's habitable zone, according to reports posted Wednesday on Twitter by astronomers attending the Search for Life Beyond the Solar System conference in Tucson, Ariz.
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The outermost planet has a radius that is estimated to be 1.1 times as big as Earth's, Nick Ballering, an astronomy graduate student at the University of Arizona, and scientist Jessie Christiansen, with the Ames Research Center, wrote in separate posts on Twitter.
The host star was not named, but was identified as an M1 dwarf, which is a small star that is dimmer than the sun. These types of stars, also known as "red dwarfs" comprise about 70 percent of the stars in the Milky Way galaxy.
So far, the most Earth-like planet detected by the now-defunct Kepler telescope is Kepler-62 f, which is about 1.4 times the size of Earth. Kepler-62 f receives about half as much energy from its star as Earth gets from the sun, and has an orbital period of 267 days (compared to Earth's 365 days).
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It is thought to orbit in its star's so-called "habitable zone" where temperatures are suitable for liquid surface water.
Water is believed to be necessary for life.
The Kepler telescope was launched in 2009 specifically to look for Earth-like planets beyond the solar system.
In an email to Discovery News, Barclay declined to comment on his research until it is closer to being published in a scientific journal.
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"Thanks to Barclay for the conference sneak peak of a new HZ (habitable zone) exoplanet with 1.1 (Earth radii). Can't wait to see the publications!," astronomer Kim Bott, a post-graduate student at the Australian Center for Astrobiology, posted on Twitter.