Origin and processing of water in the early Solar System

Liquid water allowed life to develop on the Earth. Yet we are still pondering on fundamental questions such as where does Solar System water come from, and when was it delivered to rocky planets in the inner Solar System? These fascinating issues motivate my interdisciplinary research across Planetary and Earth Sciences. Finding answers on the Earth may prove difficult because our planet's surface has been continuously eroded and recycled since its formation. However, asteroids whizzing around the Solar System, and to which we have access through meteorites found here on the Earth, have preserved vital records of the planet-forming epoch. Through this STFC Ernest Rutherford Fellowship I aim to characterise the water inventory in these planetary building blocks, in order to constrain the origin(s) of water in the Solar System. Eventually, a better understanding of the origin of water in our own Solar System will help interpretation of the recent discoveries of water-bearing planetesimals in extrasolar systems.

The formation of our Solar System started some 4.57 billion years ago from the collapse of a dense molecular cloud. From there it took several steps to form rocky planets in the inner Solar System: condensation of dust, agglomeration of cm-sized grains, accretion of 10-100 km-sized planetary embryos, heating and melting of some of these objects, and eventually further collisions leading to the formation of larger planets. The asteroid belt present today between the orbits of Mars and Jupiter contains leftovers of these planetary embryos that never made it to the final planet stage. This asteroid belt is the source of most meteorites found on the Earth. Studying these samples provides us with access to some of the processes that took place during the birth of our Solar System.

Different types of meteorites formed at different distances from the Sun, and at slightly different times after the Sun's formation. Some accreted directly from the disc of materials orbiting the young Sun (the chondrite group), and others formed through melting of larger bodies (the achondrite group). Previous studies on water in the early Solar System have focused on the carbonaceous chondrite meteorite group, which contains an abundance of carbon and water. However, the characteristics of water in older groups of meteorites (ordinary chondrites and early-formed achondrites) are poorly understood since very few studies have ever focused on these samples before. Is their water inventory consistent with that of the carbonaceous chondrite groups? How does it compare with comets? Were there previously unrecognised unknown water reservoirs that existed in the early Solar System? Does the isotopic signature of water vary with formation distance from the Sun? I will establish a comprehensive inventory of water in unexplored types of objects formed within 5 million years of the Solar System's formation, and integrate these new data into models of evolution of the early Solar System.

My study will provide new constraints on the origin of water in planetary building blocks and its processing during their evolution that eventually led to the formation of rocky planets. This space-related topic is timely as there are several upcoming international space missions that will visit primitive asteroids and collect materials to return to the Earth. I will leverage the excitement and the public interest for space exploration as a fantastic opportunity for engaging people towards Science. To this end I will participate in the numerous outreach activities attended by the Isotope group at the University of Manchester, and communicate my discoveries through its popular 'Earth and Solar System' blog.