New evidence of how water reached Earth

Chuck Bednar for redOrbit.com – @BednarChuck

New research led by astronomers and astrophysicists from the University of Warwick has found evidence in asteroid debris explaining how water reached Earth, and their research indicates that our planet is not alone in the amount of H2O it contains.

In a paper published Thursday in the Monthly Notices of the Royal Astronomical Society, lead researcher Dr. Roberto Raddi and his colleagues explained that water delivery through asteroids or comets is likely to be occurring in other planetary systems, just as it did on this planet.

They found evidence that numerous planetary bodies, including comets and asteroids, contained large amounts of water. The authors claim that their research seems to support the belief that H2O can be delivered to Earth-like worlds through these bodies, making it possible for planets to have a volume of water sufficient for the formation of life.

“There is currently a lot of discussion about finding other Earths, i.e. habitable planets, and there have been already various claims of an ‘Earth 2.0,’” University of Warwick professor and study co-author Boris Gänsicke told redOrbit via email. “So far, what these studies concluded is the discovery of a planet with an Earth-like size, and mass (and hence density) being located in what astronomers define habitable zone, i.e. warm enough to have liquid water.”

Proving asteroids provide the water

However, he added, “those studies are not able to tell us anything about the existence of water on those planets. Closer to home, we are not even sure about the origin of water on Earth. One often-discussed hypothesis is that water was delivered by comets or asteroids. Our study ties both ends of this story together.”

Using the William Herschel Telescope in the Canary Islands, Dr. Raddi, Professor Gänsicke and their colleagues were able to detect large quantities of hydrogen and oxygen in the atmosphere of SDSS J1242+5226, a white dwarf star that was once similar to the sun. The amount of elements provided new evidence that an exo-asteroid that was once rich in ice or hydrate metals ventured too close to the star, was disrupted, and eventually delivered its water to the star.

That asteroid, they explained, was roughly the same size as Ceres, the largest asteroid currently in the solar system, and the amount of water found around SDSS J1242+5226 was equal to about 30 percent to 35 percent that of the oceans found on Earth. The impact of this type of water-rich asteroid resulted in hydrogen and oxygen being mixed into the atmosphere.

“Our analysis… shows that water-rich asteroids that can provide to planets in the habitable zone exist,” Professor Gänsicke explained to redOrbit. “We then went on and looked at a larger set of white dwarfs, and found strong evidence that many of them are hit over their long life times by water-rich asteroids or comets. This shows that in other planetary systems there seems to be no shortage of water carriers that could deliver oceans to other Earth-like planets.”

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