An international research team has found that four Earth-sized planets revolve around the Tau-Ceti Sun's analogue star. Two of them are in the habitable zone and could be potentially viable.
An international research team from the University of California at Santa Cruz has found that 4 planets, similar in size to Earth, orbit the nearest solar-type star, Tau Ceti, which is about 12 light years away and visible to the naked eye. The masses of these planets are only 1.7 Earth masses; they are some of the smallest planets ever recorded around the Sun's closest analogue stars. The two planets are super-earths found in the habitable zone of a star (which means they can have liquid water on their surface).
Astronomers spotted the planet's data by observing the fluctuations in the movement of the Tau Ceti. To do this, they used methods sensitive enough to detect deviations in the motion of the star, occurring at a speed of 30 centimeters per second.
Comparison of four planets of our solar system (bottom) and four planets orbiting Tau Ceti (top)
According to Steven Vogt, professor of astronomy and astrophysics, researchers are now crossing an important milestone: thanks to very sophisticated simulations of large amounts of data (collected from different observers), they can separate the noise caused by the activity of the stellar surface from the very weak signals generated gravitational jolts of planets similar in mass to the Earth.
According to lead researcher Fabo Feng, scientists have begun using new techniques to remove noise from data; this will allow the detection of weak planetary signals and will assist in the detection of Earth-like planets.
The two outer planets orbiting Tau Ceti may be habitable, but the massive remnant disk (a disk of dust and debris in stellar orbit) reduces this likelihood, as it actively bombards the planets with asteroids and comets.
Astronomers continue to refine their methods by learning to distinguish planetary wobbles from wobbles caused by active stellar surfaces. This, according to study co-author Mikko Tuomi, will test whether the two discovered outer planets around the star Tau Ceti are potentially viable.
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The study was published in the Astrophysical Journal.