Published: Thu, August 10, 2017
Research | By Jo Caldwell

Scientists discover two potentially habitable 'super-Earth' planets

Scientists discover two potentially habitable 'super-Earth' planets

Scientists have found tantalizing signs that there are four Earth-like planets orbiting Tau Ceti, a Sun-like star just 12 million light-years away.

Previous year we learned the nearest star beyond our sun has a planet about the size of Earth, but it's very different than our solar system and not an ideal candidate for finding alien life.

Scientists believe two of the planets are located in an area that is not too cold or hot to support liquid surface water - vital for sustaining alien life.

And the planets have a surface temperature ranging from zero to 100 degrees celsius - the temperature region which is flawless for supporting life.

The planets were detected by observing the wobbles in the movement of tau Ceti.

Spectroscopy is a technique that, according to NASA's website "measures light that is emitted, absorbed, or scattered by materials". The newly discovered planets correspond to detecting variations in the movement of the star as low as 30 cm/s, whilst 10 cm/s is the upper limit required for detecting an Earth analog - a planet or moon with environmental conditions similar to those found on the planet Earth.

A study published in 2013, with research by the same team, lay the groundwork for the breakthrough.

Lead study author Fabio Feng of the University of Hertfordshire told Gizmodo that we should be cautious defining the habitable zone of exoplanets, but he said he regards the two outer planets as "habitable zone candidates", especially since their orbital periods are not precisely known. It also revealed that two of the planets, Tau Ceti e and Tau Ceti f, lay inside the star's habitable zone.

The scientists used the method of "fluctuations" of the planet, izmerena the influence of gravitational interaction of a star. Tau Ceti, a favorite destination of writers of science fiction, very similar to the Sun in size and brightness.

Neither of Tau Ceti's "super-Earths" lie in the center of its habitable zone. "Our detection of such weak wobbles is a milestone in the search for [Earth-like exoplanets] and the understanding of the Earth's habitability through comparison with these".

The Herefordshire-Santa Cruz team previously collaborated on a study of Tau Ceti in 2013, a study that concluded that five much larger "super-Earth" planets orbited the star. Unlike more common smaller stars, such as the red dwarf stars Proxima Centauri and Trappist-1, they are not so faint that planets would be tidally locked, showing the same side to the star at all times.

"Despite how we look on the star, it seems that she has at least four rocky planets", said Dr. Tuomi. But for now, they are the best candidates we have for habitable extrasolar planets close to home.

A paper on the new findings was accepted for publication in the Astrophysical Journal and is available online.

Still, the researchers say we shouldn't get carried away with ourselves here, because a huge ring of space debris surrounds the Tau Ceti system, meaning these alien worlds - lifeless or not - could be threatened by intensive bombardment from asteroids and comets.

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