The ancient heritage of water ice in the solar system

L. Ilsedore Cleeves, Edwin A. Bergin, Conel M. O’D. Alexander, Fujun Du, Dawn Graninger, Karin I. Öberg, Tim J. Harries


Science 26 September 2014:
Vol. 345 no. 6204 pp. 1590-1593
DOI: 10.1126/science.1258055

Identifying the source of Earth’s water is central to understanding the origins of life-fostering environments and to assessing the prevalence of such environments in space. Water throughout the solar system exhibits deuterium-to-hydrogen enrichments, a fossil relic of low-temperature, ion-derived chemistry within either (i) the parent molecular cloud or (ii) the solar nebula protoplanetary disk. Using a comprehensive treatment of disk ionization, we find that ion-driven deuterium pathways are inefficient, which curtails the disk’s deuterated water formation and its viability as the sole source for the solar system’s water. This finding implies that, if the solar system’s formation was typical, abundant interstellar ices are available to all nascent planetary systems.”
Update (26 September):

Earth has water older than the Sun
Not all water in the Solar System today could have formed here, researchers say.
by Elizabeth Gibney

nature, 26 September 2014