Astronomers have discovered an Earth-like planet located just twelve light years from Earth, the closet yet discovered.
An international team of scientists, including Carnegie’s Paul Butler, reportedly discovered that Tau Ceti, one of the closest and most Sun-like stars, may have five planets — one of which is located within the “habitable zone.”
“We are now glimpsing for the first time the secrets of our nearest companion stars and their previously hidden reservoirs of potentially habitable planets,” Butler said. “This work presages the time when we will be able to directly see these planets, and search them for water, carbon dioxide, methane, and other signposts of life.”
At a distance of twelve light years and visible with a naked eye in the evening sky, Tau Ceti is the closest single star with the same spectral classification as our Sun, according to astronomers. The star is thought to have five planets, which are estimated to have masses between two and six times the mass of the Earth. One of the planets lies in the habitable zone of the star and has a mass around five times that of Earth, making it the smallest planet found to be orbiting in the habitable zone of a Sun-like star.
The international team of astronomers, led by Mikko Tuomi from the University of Hertfordshire, announced the findings after combining more than six-thousand observations from three different instruments and applied intensive modeling to the data. Using new techniques, the team found a method to find signals half the size previously thought possible, which greatly improves the sensitivity of searches for small planets.
“We pioneered new data modeling techniques by adding artificial signals to the data and testing our recovery of the signals with a variety of different approaches,” Tuomi said. “This significantly improved our noise modeling techniques and increased our sensitivity to find low mass planets.”
The announcement comes as NASA’s Kepler Space Telescope has discovered more than 2,000 planets orbiting other worlds. So far, hundreds of Earth-size planet candidates have been found as well as candidates that orbit in the habitable zone, the region in a planetary system where liquid water might exist on the surface of a planet. None of the candidates is exactly like Earth.
Their work is published by Astronomy & Astrophysics and is available online.