Water Rich Rocky Planetary Body Found Orbiting a White Dwarf

A group of astronomers for the first time have discovered water in an asteroid orbiting a dying star dubbed GD61 outside our solar system. The finding suggests that the celestial object could have supported life.

Scientists at the Universities of Warwick and Cambridge have discovered large amount of water in the debris of an exoplanet that is surrounding a white dwarf star called GD61. This finding suggests  the existence of earth-like habitable bodies.

 The observation was made using the Hubble Space Telescope and the Keck telescope in Hawaii.  This new discovery claims that the star GD 61 and its planetary system that is located 150 light years away, once had the potential to hold Earth like exoplanets.

This is the first time that the astronomers have discovered two major elements essential for habitation i.e. 'water' and 'rocky surface', beyond our solar system.

Earth is a dry planet with just 0.02 percent of its mass as surface water. When the water-rich asteroids in the solar system collided with our planet it gave rise to the formation of oceans. This new discovery claims that such a similar water delivery system may have occurred in the distant dying star's solar system.

"The finding of water in a large asteroid means the building blocks of habitable planets existed - and maybe still exist - in the GD 61 system, and likely also around substantial number of similar parent stars," lead author Jay Farihi, from Cambridge's Institute of Astronomy, said in a press statement. "These water-rich building blocks, and the terrestrial planets they build, may in fact be common - a system cannot create things as big as asteroids and avoid building planets, and GD 61 had the ingredients to deliver lots of water to their surfaces. Our results demonstrate that there was definitely potential for habitable planets in this exoplanetary system."

According to the researchers, the water discovered came from a small planet that is nearly 90 km in diameter and once orbited the GD 61 star before it turned into a white dwarf some 200 million years ago.

The researchers calculated the components of the shredded asteroid and claim that this is parallel to dwarf planet Ceres in the Earth' solar system that consists of 26 percent water. They claim the dying asteroid is as wet as Ceres. They confirmed that the debris belonged to an asteroid and not a comet as the pieces had no carbon, the main component of a comet.

The range of elements found in the white dwarf is vast consisting of magnesium, silicon and iron, along with oxygen. The scientists say the giant was probably torn apart by the gravitational pull of the white dwarf.

Team member Detlev Koester from the University of Kiel concludes that, "These asteroids tell us that the GD 61 system had - or still has - rocky, terrestrial planets, and the way they pollute the white dwarf tells us that giant planets probably still exist there. This supports the idea that the star originally had a full complement of terrestrial planets, and probably gas giant planets, orbiting it - a complex system similar to our own."

Their findings are published in the journal Science.