Exo-asteroid debris shows how water reached Earth

A new research has suggested that water delivery via asteroids or comets is likely taking place in many other planetary systems, just as it happened on Earth.

The research finds evidence for numerous planetary bodies, including asteroids and comets, containing large amounts of water, adding further support to the possibility water can be delivered to Earth-like planets via such bodies to create a suitable environment for the formation of life.

Commenting on the findings lead researcher Roberto Raddi of the University of Warwick said that the research has found that, rather than being unique, water-rich asteroids similar to those found in our Solar System appear to be frequent. Accordingly, many of planets may have contained a volume of water, comparable to that contained in the Earth.

Raddi added that it is believed that the Earth was initially dry, but the research strongly supports the view that the oceans we have today were created as a result of impacts by water-rich comets or asteroids.

In observations obtained at the William Herschel Telescope in the Canary Islands, the University of Warwick astronomers detected a large quantity of hydrogen and oxygen in the atmosphere of a white dwarf (known as SDSS J1242+5226). The quantities found provide the evidence that a water-rich exo-asteroid was disrupted and eventually delivered the water it contained onto the star.

The asteroid, the researchers discovered, was comparable in size to Ceres - at 900km across, the largest asteroid in the Solar System. The amount of water found SDSS J1242+5226 is equivalent to 30-35 percent of the oceans on Earth, explained Raddi.

The impact of water-rich asteroids or comets onto a planet or white dwarf results in the mixing of hydrogen and oxygen into the atmosphere. Both elements were detected in large amounts in SDSS J1242+5226.

The study is published by Royal Astronomical Society.