Habitable world discovered orbiting ‘Sun’s twin’ just 12 light years away
December 19, 2012 in Weird News
*The planet is one of five orbiting Tau Ceti, a star which is almost identical to our own Sun
*It is five times the mass of Earth, but sits in Tau Ceti’s habitable zone, where temperatures are just right for stable, liquid water
*An international team made the discovery by combining more than 6,000 observations from three different telescopes
A planet that could support life orbits a twin of our own Sun which is so close it is visible to the naked eye, scientists revealed today.
The world is one of five thought to be circling Tau Ceti, a star just 12 light years away which is almost identical to the sun.
Astronomers estimate the Tau Ceti planets to be two to six times bigger than Earth. One of them, with five times the Earth’s mass, lies in the star’s ‘habitable zone’.
An artist’s impression of the Tau Ceti system: A planet with conditions that could support life orbits the system, whose star is almost a twin of our own Sun, scientists revealed today
Also known as the ‘Goldilocks zone’, this is the orbital region that is neither to hot nor too cold to allow liquid surface water and, potentially, life.
Tau Ceti can be seen in the night sky in the constellation of Cetus, the whale. Details of the discovery are to appear in the journal Astronomy & Astrophysics.
Because of the difficulties involved in detecting extra-solar planets, most found so far have had high masses.
The Tau Ceti planetary family is thought to be the lowest mass solar system yet detected.
Scientists from Australia, Britain, Chile and the U.S. found the planets using a highly sensitive technique that combined data from more than 6,000 observations from three different telescopes.
They used the radial velocity method which looks for ‘wobble’ in a star’s movement caused by the gravitational tug of planets.Dr James Jenkins, a member of the international team from the University of Hertfordshire, said: ‘Tau Ceti is one of our nearest cosmic neighbours and so bright that we may be able to study the atmospheres of these planets in the not-too-distant future.
‘Planetary systems found around nearby stars close to our sun indicate that these systems are common in our Milky Way galaxy.’
More than 800 planets have been discovered orbiting stars beyond the sun since the Nineties. Those found around the nearest sun-like stars are the most interesting to astronomers.
‘This discovery is in keeping with our emerging view that virtually every star has planets, and that the galaxy must have many such potentially habitable Earth-sized planets,’ said Steve Vogt, a veteran exoplanet-hunter.
‘We are now beginning to understand that Nature seems to overwhelmingly prefer systems that have multiple planets with orbits of less than one hundred days,’ he said in a press release published by Britain’s University of Hertfordshire.
‘This is quite unlike our own solar system where there is nothing with an orbit inside that of Mercury. So our solar system is, in some sense, a bit of a freak and not the most typical kind of system that Nature cooks up.’
Professor Chris Tinney, an Australian member from the University of New South Wales, said: ‘As we stare at the night sky, it is worth contemplating that there may well be more planets out there than there are stars, some fraction of which may well be habitable.’
Dr Jenkins is a visiting fellow at the University of Hertfordshire who is based at the University of Chile.
SO-CLOSE AND YET SO FAR…
Tau Ceti is a star in the constellation Cetus that is spectrally similar to the Sun, although it has only about three-quarters of the Sun’s mass.
At a distance of just under 12 light years from the Solar System, it is a relatively nearby star. Given its stability, similarity and relative proximity to the Sun, Tau Ceti is consistently listed as a target for the Search for Extra-Terrestrial Intelligence (SETI), and it appears in some science fiction literature.
Tau Ceti does not have a widely-recognised traditional name, but it can nevertheless be seen with the unaided eye as a third-magnitude star.
As seen from Tau Ceti, our own Sun would be a third-magnitude star in the constellation Boötes.