Origin and processing of water in the early Solar System

液态水使地球上的生命得以发展。然而，我们仍然在思考一些基本的问题，比如太阳系的水从哪里来，它是什么时候被送到太阳系内部的岩石行星上的？这些引人入胜的问题激励着我在行星科学和地球科学之间进行跨学科研究。在地球上找到答案可能会被证明是困难的，因为我们星球的表面自形成以来一直被侵蚀和回收。然而，围绕太阳系旋转的小行星--我们可以通过地球上发现的陨石接触到这些小行星--保存了行星形成时代的重要记录。通过STFC的欧内斯特·卢瑟福奖学金，我的目标是描述这些行星积木中的水库存，以便限制太阳系水的起源(S)。最终，更好地了解我们太阳系中水的起源将有助于解释最近在太阳系外发现的含水小行星。我们太阳系的形成始于大约45.7亿年前稠密的分子云的坍塌。从那时起，在太阳系内形成岩石行星经历了几个步骤：尘埃凝结，厘米大小的颗粒聚集，10-100公里大小的行星胚胎积累，其中一些天体加热和融化，最终进一步的碰撞导致更大行星的形成。今天存在于火星和木星轨道之间的小行星带包含了这些从未进入行星最后阶段的行星胚胎的残留物。这个小行星带是地球上发现的大多数陨石的来源。研究这些样本为我们提供了了解太阳系诞生期间的一些过程的途径。不同类型的陨石在离太阳不同的距离形成，在太阳形成后的时间略有不同。有些是直接从围绕年轻太阳运行的物质盘中吸积而来的(球粒陨石群)，另一些则是通过较大的天体熔化而形成的(无球粒陨石群)。以前对太阳系早期水的研究主要集中在碳质球粒陨石群上，它含有丰富的碳和水。然而，较老的陨石群(普通球粒陨石和早期形成的非球粒陨石)中的水的特征了解得很少，因为以前很少有研究关注这些样品。它们的水储量与碳质球粒陨石群的水储量是否一致？它与彗星相比如何？早期太阳系中是否存在以前未被发现的未知蓄水池？水的同位素特征会随着离太阳的形成距离而变化吗？我将建立一个关于太阳系形成500万年内形成的未知类型天体中水的全面清单，并将这些新数据整合到早期太阳系演化的模型中。我的研究将为行星积木中水的来源及其在演化过程中的处理提供新的限制，最终导致岩石行星的形成。这一与空间有关的专题是及时的，因为即将进行的几次国际空间飞行任务将访问原始小行星并收集返回地球的材料。我将利用人们对太空探索的兴奋和公众兴趣，将其作为吸引人们从事科学的绝佳机会。为此，我将参加曼彻斯特大学同位素小组参加的众多外展活动，并通过其广受欢迎的“地球和太阳系”博客交流我的发现。

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.