Asteroids, comets delivering water to planetary bodies universally: Research

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Asteroids and comets have been pegged as the initial source of water on Earth and a new research strengthens this possibility while also stating that these space rocks are involved in water delivery on many other planetary systems.

The research led by researchers at University of Warwick found evidence of planetary bodies including including asteroids and comets containing large amounts of water thereby strengthening the idea that water and life could be much more common on Earth-like planets across the universe.

Dr Roberto Raddi, of the University of Warwick’s Astronomy and Astrophysics Group, said: “Our 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 though Earth was initially dry, their research strongly suggests that oceans, as we see today, were created as a result of impacts by water-rich comets or asteroids.

Some of the main points of the research are:

  • Quantity of water on Earth not unique
  • Water likely reached Earth via comets and asteroids crashing into Earth’s surface
  • Evidence found in the atmosphere of white dwarf star
  • Asteroid found to contain 30-35% Earth’s water content

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% of the oceans on Earth”, explained Dr 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.

Research co-author Professor Boris Gänsicke, also of University of Warwick, explained: “Oxygen, which is a relatively heavy element, will sink deep down over time, and hence a while after the disruption event is over, it will no longer be visible.

“In contrast, hydrogen is the lightest element; it will always remain floating near the surface of the white dwarf where it can easily be detected. There are many white dwarfs that hold large amounts of hydrogen in their atmospheres, and this new study suggests that this is evidence that water-rich asteroids or comets are common around other stars than the Sun”.

The research, Likely detection of water-rich asteroid debris in a metal-polluted white dwarf, is published in the Monthly Notices of the Royal Astronomical Society by Oxford University Press.