Does Half Our Water Come from the Sun?

Remember the Japanese mission to get a piece of an asteroid? It happened in 2011 and work is still being done on the samples returned. THIS ARTICLE records what one team discovered on some tiny particles of the asteroid. The article is based on THIS ACADEMIC PAPER which has not yet been fully published.

Using atom probe tomography they found that the surface of the particles was rich in hydroxide (OH), and much more surprisingly water molecules (H₂O).

The most likely source of the hydrogen atoms is the solar wind which consists of hydrogen ions. The conducted experiments to prove this was possible.

And their conclusion was that half of the Earths water came from this source in the time that the Earth was forming - there were lots of asteroidy things basking in the suns light at this time. And this would explain the isotopic composition of the Earth's water which is otherwise difficult to understand.

The asteroid Itokawa was the source of grains of dust which contained a surprising layer of water. JAXA