Experimenting with the Earliest Stages of Planet Formation

总体目标：我们的科学目标是定性和定量地描述在冰质小行星形成的最早阶段占主导地位的碰撞，以回答“行星是如何形成的？“我们是世界上四个以经验为基础的小组之一，利用实验室实验来测试冰粒碰撞，利用抛物线和亚轨道飞行中的微重力持续时间和质量，研究微米大小的冰粒集合体之间的厘米到亚厘米s-1碰撞，形成微米-毫米大小的'蓬松'冰聚集体，粘在一起形成厘米大小的冰'卵石'。这些“成分”构成了原行星盘中物质聚集的基础（包括我们自己的前太阳星云）形成行星，彗星和小行星的核心。这个博士：该博士将专注于实验室工作，以生产和制造此类实验所需的多孔无定形冰颗粒，从实验室中的概念实验的粗略证明，到冰颗粒的大规模可重复生产，这将通过中子散射实验和红外光谱学来表征，并且其行为将在落塔和抛物线飞行实验中进行测试。博士学位提供了国际和工业合作的范围，并将包括重要的设施使用，需要数周的“原位”实验远离地球。还有机会将研究应用于了解使命数据（例如Rosetta、OSIRIS雷克斯、火卫一样品返回）和天文观测（例如JWST和阿尔马）。

Overarching aim: Our scientific goal is to describe, qualitatively and quantitatively, the collisions that dominate the earliest stages of icy planetesimal-formation, to answer, "how do planets form?" We are one of four groups world-wide approaching this empirically, using laboratory experiments to test icy grain collisions, taking advantage of the microgravity duration and quality in parabolic and sub-orbital flight, to study cm to sub-cm s-1 collisions between ensembles of um-sized icy grains, forming um - mm sized 'fluffy' ice aggregates, that stick to form cm-sized icy 'pebbles'. These "ingredients" form the basis of material that aggregates in protoplanetary disks (including our own pre-solar nebula) to form the cores of planets, comets and asteroids.This PhD: This PhD will focus on laboratory work to produce and characterise the porous amorphous icy particles required for such experiments, moving from coarse proof of concept experiments in the laboratory, to large-scale reproducible production of icy grains, which will be characterised through neutron scattering experiments, and IR spectroscopy, and whose behaviour will be tested in drop tower and parabolic flight experiments. The PhD offers scope for international and industrial collaboration, and will include significant facilities use requiring week(s) on "in situ" experimentation away from the OU. There is also an opportunity to apply the research to understanding of mission data (e.g. Rosetta, OSIRIS Rex, Phobos sample return), and astronomical observations (e.g. JWST and ALMA).