A rich asteroid water gives credence to the theory of life on ... - 20minutes.fr

life could be possible on other planets outside our solar system that is suggested by the discovery for the first time, the remains of a large asteroid rich in water in another stellar system <. / p>

Never before had all detected outside our solar system water and rocky bodies – the “two key elements” for a planet is habitable – point researchers in a study published European Thursday in the journal Science.

previous observations of 12 exoplanets whose remains were destroyed in orbit around white dwarfs – stars at the end of life who have exhausted their nuclear fuel – did not show the presence of water

dying star

In the study published Thursday, the remnants of an asteroid that had to be at least 90 km in diameter, are in orbit probably other planets around a white dwarf called GD 61 located approximately 170 light-years from Earth – a light year equals 9.460 billion km

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“At this stage of his life all that remains of the rocky body is dust and debris around the dying star,” commented Professor Boris Gänsicke, Department of Physics, University of Warwick, UK, one of the main co-author of the study.

“But this global cemetery is a rich source of information,” he says, “these remnants contain chemical evidence revealing the existence of this ancient water-rich rocky asteroid”

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dwarf planet composed of 26% water

These astrophysicists also detected in the debris, magnesium, silicon, iron and oxygen, which are the key ingredients of rocks.

Bigger than the sun

rocky planets like Earth formed by the aggregation of asteroids and “the fact of finding so much water in such a celestial body size means that the materials forming habitable planets and planets as they- themselves have existed or still exist in the GD 61 and probably in many other similar systems “star system, reports Jay Farihi, an astrophysicist at the Institute of Astronomy at Cambridge, the main author of this discovery.

asteroid that was perhaps a dwarf planet, was formed in 26% water, a proportion similar to Ceres in our solar system. In comparison, the Earth is very dry because the water is only 0.02% of its mass. As Ceres, water should be in the form of ice under the surface of the asteroid.

In his previous life, GD 61 was a little larger than our Sun, which in several billion years suffer the same fate star.

part of the system has survived

According to these

astrophysicists GD 61 has finally exhausted its fuel there 200 million years to become a white dwarf. Part of its planetary system survived, but not asteroids and dwarf planets, which orbit is then much closer to the dying star, where they were destroyed by its gravitational force.

For this research, the scientists relied primarily on observations from a spectrograph on board the Hubble Space Telescope using the ultraviolet rays that can be made from the ground because the Earth’s atmosphere blocks the radiation .

AFP