Heavy water detected in protoplanetary disk for first time
The discovery of ancient water in the circumstellar disk of a newborn star indicates that the water in the comets and on Earth may be older than the Sun. The discovery provides insights into the origin and history of water in the Solar System.
Astronomers have discovered the first evidence of heavy water, or doubly deuterated water in a planet forming disk surrounding the newborn star V883 Ori. The discovery was made using the ground-based Atacama Large Millimeter/submillimeter Array (ALMA) instrument in the deserts of Northern Chile. The water in the planet-forming disk is far older than the star itself, having journeyed through space from ancient molecular clouds. The implication of the discovery is that the water in the Solar System, including the water in our comets and on Earth, may be far older than the Sun. Your morning cup of coffee may be older than the Sun.
The chemical fingerprinting of the heavy water molecules indicate that they survived the violent processes of star and planet formation, traversing billions of km across interstellar space before reaching the systems they are in today. The discovery challenges the notion that water is utterly broken down to its constituent elements and then reformed in the disk, indicating that the bulk of the water is inherited from the earliest and coldest stages of star formation. The research is a major breakthrough in improving the understanding of the history of water in our own Solar System, as well as all other star systems.
Implications for the search for life
A paper describing the research has been published in Nature Astronomy. Second author of the paper, John Tobin says, "Until now, we weren’t sure if most of the water in comets and planets formed fresh in young disks like V883 Ori, or if it’s ‘pristine,’ originating from ancient interstellar clouds." At least on Earth, where there is water, there is life. Water is widely considered to be fundamental to planetary habitability. If worlds across the universe can inherit water billions of years older than themselves, the life that inhibits it could be deeply connected to the ancient past of the universe. The discovery is another sign pointing to life being an astrophysical process, as against a geological one.