The cosmic carbon observatory

This research programme seeks to understand key processes during the early history of the Solar System including the construction and destruction of planetary bodies, and delivery of some of the key ingredients for life to Earth, including carbon and water.

One focus of this project is on 'carbonaceous' asteroids that are made of rocks that are rich in water and organic matter. If enough fragments of these asteroids had fallen to the Earth early in its history, they could have introduced sufficient water and organic matter to help life to start. In recognition of their scientific importance, two carbonaceous asteroids, named Bennu and Ryugu, are currently being studied by spacecraft sent by NASA and the Japanese Aerospace Exploration Agency, respectively. These spacecraft have collected samples to deliver to Earth; Hayabusa2 successfully delivered ~5 g of Ryugu in December 2020. We will study these samples to understand how much water the asteroid now contains. One theory is that less water is present now than when the asteroid formed, and was lost as the asteroid was heated from the inside. We will try to answer this question by analysing samples from Ryugu, and interpreting them using information from experiments. These experiments will simulate the effects of heating of the asteroid's interior, and irradiation of Ryugu's surface by hydrogen and helium from the Sun (called the solar wind).

In another project we will investigate how the same process of solar wind irradiation could have added water to otherwise completely dry mineral grains within the disk of dust within which the Solar System was born. We will also evaluate how much of the water that has been created by this process may provide an accessible resource on the surfaces of airless worlds. This work will use extraterrestrial materials that have been exposed to the solar wind on the surfaces of asteroids and the Moon. Alongside this work, experiments will mimic the effects of solar wind on mineral grains. The amount of water in both sets of samples will be measured using a new and very powerful technique called atom probe tomography; this technique enables scientists to see the locations of atoms of various types and water molecules within a sample and in three dimensions.

The formation, compaction and aqueous evolution of carbonaceous asteroids, as well as how many of them were present initially in the proto-Solar System, is a hotly debated topic. Clues to the diversity of processes at work within these primitive bodies can be understood by exploring the microstructure and texture of meteorites and samples returned from these bodies. Using a multi-dimensional correlative approach underpinned by big data principles, we will group these materials by their texture and in so doing understand the dominant processes at work on primitive asteroids, and constrain how many there were.

In order to send fragments to Earth, the carbonaceous asteroids must have experienced collisions. There is also evidence of a much more violent event in the early history of the Solar System that led to the breakup of a body the size of Mercury or Mars. Fragments of this planet-size body have fallen to Earth as the ureilite meteorites. These rocks are very special as they contain minerals rich in carbon, including diamonds, that come from deep inside the planet. The chemical composition of these minerals and the rocks within which they occur can tell us much about the carbon cycle of this doomed planet, and how other planets including Earth formed and evolved.

The Cosmic Carbon Observatory will leverage cutting edge correlative micro to atomic scale analysis of precious extraterrestrial materials and thereby transform our understanding of crucial carbon-driven processes in the Solar System.