A new study by a team of astronomers from the United States and United Kingdom reveals that four Earth-sized planets have been discovered revolving around the nearby star Tau Ceti. Scientists have discovered two potentially habitable planets orbiting a sun just 12 light-years away.
Tau Ceti is so similar to our sun that Toumi says, "they might as well be twins".
Two planets that orbit around a star like our own sun could support life, according to new research, reported The Independent.
Instead, the team observed wobbles in the star's movement as small as 30 centimeters (one foot) per second.
With the introduction of new technologies to get rid of the noise in the data, the scientists were able to register the find. The outer two planets in the system, tau Ceti-f and tau Ceti-e are super Earths, and in the habitable zone of the star.
However, living there may not be straightforward as there is evidence of a debris disc circling Tau Ceti, making it more likely that asteroids and comets could hit the planets.
Stars the size of the Sun are the best targets for finding habitable Earth-seized planets.
"We detected the planets by measuring the tiny periodic wobbles caused to the host star, Tau Ceti, by the gravitational pull of the planets orbiting it", Mikko Tuomi, an astronomer from the University of Hertfordshire and coauthor of the study, told Digital Trends.
The planets were detected using the "wobble" method, whereby astronomers monitor any wobbles made by a star. But even if none of tau Ceti's planets are remotely habitable, the existence of such nearby cosmic neighbors would be a boon to search for life beyond Earth. The team used the HARPS spectrograph of the European Southern Observatory in Chile and the Keck-HIRES instrument in Mauna Kea in Hawaii.
"We realized that we could see how star's activity differed at different wavelengths and use that information to separate this activity from signals of planets". Two of those worlds, tau Ceti e and f, were thought to possibly be at the right distance to harbor liquid water, although with mass estimates of 4.6 and 6.6 Earths, these potential worlds probably weren't rocky. The star is slightly smaller than the Sun, and less active, and is about 12 light years away.
As already mentioned, the four planets were found orbiting Tau Ceti, but the two inner planets were actually first detected and confirmed in 2013. Numerous other "potentially habitable" exoplanets discovered to date orbit dim red dwarf stars, which, for a variety of reasons, could prove hostile to life.
"We came up with an ingenious way of telling the difference between signals caused by planets and those caused by a star's activity", Dr. Tuomi explained.