Trappist-1 planets have water, may be 'habitable': researchers

APD NEWS

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Seven planets recently spotted orbiting a dim star in our Milky Way galaxy are rocky, seem to have water, and are potentially "habitable", researchers studying the distant system said Monday.

Though much remains unknown about the planets' surfaces and atmospheres, the new measurements have not ruled out the possibility that they may harbor even rudimentary life, the scientists reported.

An artist’s impression shows an imagined view from the surface of a planet orbiting an ultracool dwarf star 39 light years away from Earth discovered using the "TRAPPIST" telescope at ESO’s La Silla Observatory in Chile.

"So far, no sign allows us to say that they are not habitable," said University of Birmingham astronomer Amaury Triaud, the co-author of a study on the subject.

"All the traffic lights we have passed so far are green."

Research teams gleaned more information about the dwarf star at the center of the Trappist-1 system, as well as improved measurements of the size and mass of each planet, and the composition of their atmospheres.

All seven are mostly made of rock, with up to five percent of their mass in water – though it may be in the form of gas or ice, or trapped deep inside the rocky orbs, researchers said.

On Earth, the oceans account for about 0.02 percent of our planet's mass.

A year ago, researchers announced the discovery of the seven Earth-like planets orbiting Trappist-1, an "ultracool" red dwarf star some 39 light years from our home.

As for the odds of the planets hosting organic life forms, "we cannot say at this stage, as they are vastly different from the only planet we know to harbor life (Earth)," Triaud told AFP.

"But they have suitable characteristics and are to date the best place beyond the edge of our (Solar) system to search."

The presence of liquid water is considered essential for life to exist anywhere.

Astronomers used the Hubble Space Telescope to learn more about the Trappist system by studying the planets' atmospheres as they passed in front of their star, appearing as a dark, traveling dot from the observer's point of view.

Findings were published Monday in two papers in the journals Nature Astronomy, and Astronomy and Astrophysics.

(AFP)