The cosmic carbon observatory

该研究项目旨在了解太阳系早期历史的关键过程，包括行星体的构建和破坏，以及向地球输送生命的一些关键成分，包括碳和水。这个项目的一个重点是“碳质”小行星，它是由富含水和有机物的岩石组成的。如果在地球早期有足够的小行星碎片落在地球上，它们可能会带来足够的水和有机物质，帮助生命的开始。由于认识到它们在科学上的重要性，美国宇航局和日本宇宙航空研究开发机构目前分别派出航天器对两颗名为本努和龙宫的碳质小行星进行研究。这些航天器收集了样本并将其送到地球；隼鸟2号于2020年12月成功运送了约5克的龙宫。我们将研究这些样本，以了解这颗小行星现在含有多少水。一种理论认为，现在存在的水比小行星形成时要少，并且随着小行星内部的加热而消失。我们将尝试通过分析来自龙宫的样本来回答这个问题，并使用实验信息来解释它们。这些实验将模拟小行星内部加热的影响，以及来自太阳的氢和氦（称为太阳风）对龙宫表面的照射。在另一个项目中，我们将研究相同的太阳风辐射过程如何在太阳系诞生的尘埃盘中完全干燥的矿物颗粒中添加水。我们还将评估通过这一过程产生的水有多少可能在无空气的星球表面提供可获取的资源。这项工作将使用小行星和月球表面暴露在太阳风下的外星物质。在这项工作的同时，实验将模拟太阳风对矿物颗粒的影响。两组样品中的含水量将使用一种新的非常强大的技术——原子探针断层扫描（atom probe tomography）来测量；这项技术使科学家能够在三维空间内看到样品中各种类型的原子和水分子的位置。碳质小行星的形成、压实和含水演化，以及它们中有多少最初出现在原始太阳系中，是一个激烈争论的话题。通过探索陨石的微观结构和质地以及从这些天体中返回的样本，可以了解这些原始天体中工作过程多样性的线索。使用以大数据原理为基础的多维相关方法，我们将根据这些材料的纹理对它们进行分组，从而了解原始小行星上的主要过程，并限制它们的数量。为了将碎片送到地球，碳质小行星必须经历碰撞。还有证据表明，太阳系早期历史上发生过一次更为剧烈的事件，导致了一个水星或火星大小的天体的解体。这个行星大小的天体的碎片以陨石的形式落到地球上。这些岩石非常特别，因为它们含有富含碳的矿物质，包括来自地球深处的钻石。这些矿物和岩石的化学成分可以告诉我们很多关于这个注定要灭亡的星球的碳循环，以及包括地球在内的其他行星是如何形成和演化的。宇宙碳天文台将利用尖端的相关微观到原子尺度分析宝贵的地外物质，从而改变我们对太阳系中关键碳驱动过程的理解。

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.