The nearest Earthlike planets could be just 13
light-years away, putting them in our cosmic "back yard", astronomers
have claimed.
 |
| An artist's conception of a hypothetical habitable planet with two moons orbiting a red dwarf star |
Six
per cent of red dwarfs, the most common stars in our galaxy, have Earth-sized
planets which could be habitable, according to data from Nasa's Kepler space
telescope.
On this basis, experts from the Harvard-Smithsonian Centre for Astrophysics calculated that the closest Earthlike world is probably as close as 13 light-years to Earth.
Courtney Dressing, a graduate student who led the study, said: "We thought we would have to search vast distances to find an Earthlike planet. Now we realise another Earth is probably in our own backyard, waiting to be spotted."
Red dwarfs, which are smaller and cooler than our Sun, are not visible from Earth with the naked eye but make up 75 per cent of the stars in our galaxy, numbering about 75 billion.
The researchers identified all the red dwarfs in a sample of 158,000 stars catalogued by Kepler and calculated their size and temperature, discovering that most were smaller and cooler than previously thought.
They identified 95 candidate planets orbiting these stars, and found that three were both warm and about the same size as Earth. The results will be published in The Astrophysical Journal.
Overall the researchers calculated that about six per cent of all red dwarfs should have an Earth-sized planet, meaning they could estimate the likely distance to the nearest one.
This means finding life beyond the solar system should be "significantly easier" than previously thought, co-author David Charbonneau said.
Because such worlds would be closer to their parent stars than Earth is to the Sun, they would most likely be tidally locked and rely on a thick atmosphere or deep ocean to transmit heat around the planet, researchers said.
Red dwarfs live much longer than Sun-like stars, they added, meaning any life on the planets could be much older and more evolved than life on Earth.
by Nick Collins
On this basis, experts from the Harvard-Smithsonian Centre for Astrophysics calculated that the closest Earthlike world is probably as close as 13 light-years to Earth.
Courtney Dressing, a graduate student who led the study, said: "We thought we would have to search vast distances to find an Earthlike planet. Now we realise another Earth is probably in our own backyard, waiting to be spotted."
Red dwarfs, which are smaller and cooler than our Sun, are not visible from Earth with the naked eye but make up 75 per cent of the stars in our galaxy, numbering about 75 billion.
The researchers identified all the red dwarfs in a sample of 158,000 stars catalogued by Kepler and calculated their size and temperature, discovering that most were smaller and cooler than previously thought.
They identified 95 candidate planets orbiting these stars, and found that three were both warm and about the same size as Earth. The results will be published in The Astrophysical Journal.
Overall the researchers calculated that about six per cent of all red dwarfs should have an Earth-sized planet, meaning they could estimate the likely distance to the nearest one.
This means finding life beyond the solar system should be "significantly easier" than previously thought, co-author David Charbonneau said.
Because such worlds would be closer to their parent stars than Earth is to the Sun, they would most likely be tidally locked and rely on a thick atmosphere or deep ocean to transmit heat around the planet, researchers said.
Red dwarfs live much longer than Sun-like stars, they added, meaning any life on the planets could be much older and more evolved than life on Earth.
by Nick Collins
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