Unveiling planet-forming discs with the Square Kilometre Array

行星诞生于年轻恒星周围的尘埃和气体盘，但形成它们的具体机制仍然难以捉摸。即将到来的平方公里阵列（SKA）是下一代射电望远镜，比目前的仪器强大许多倍，它将有能力“揭开”行星形成盘的面纱，观察大型尘埃颗粒和分子在最冷、密度最大的区域发出的辐射，而这些区域正是行星被认为形成的位置。在这个项目中，成功的候选人将把阿塔卡马大型毫米/亚毫米阵列（ALMA）对原行星盘的最新观测与辐射传输模拟相结合，以了解SKA将如何促进我们对行星形成的理解。该项目有两个主要主题，每个主题都可以根据候选人的兴趣进行探索：1)将鹅卵石成长为行星：组装一颗年轻的行星涉及到微米大小的尘埃到厘米大小的“鹅卵石”的生长，而SKA将对原行星盘中这些鹅卵石的发射非常敏感。结合原行星盘和生长行星的流体动力学模型，您将模拟尘埃颗粒的生长和演化。你将描述行星如何塑造鹅卵石的分布，并预测SKA将如何观察不同演化阶段的圆盘。2)益生元分子通往行星的途径：对地球上关键生物过程至关重要的分子（“益生元”）在星际空间中被探测到，但它们在形成行星附近的丰度和分布仍然知之甚少。您将在天体化学圆盘模型中添加所需的物理和化学过程，以重现圆盘中大分子的最新观测结果。有了这些模型，你将预测最佳的目标、分子和转变，用SKA观察，以揭示原行星盘的益生元含量。

Planets are born in discs of dust and gas that surround young stars, but the specific mechanisms that form them remain elusive. The upcoming Square Kilometre Array (SKA), a next generation radio telescope many times more powerful than current instruments, will have the power to 'unveil' planet forming discs, observing emission from large dust grains and molecules in their coldest and most dense regions - precisely the locations at which planets are thought to form. In this project, the successful candidate will combine the latest observations of protoplanetary discs from the Atacama Large Millimetre/submillimetre Array (ALMA) with radiative transfer simulations to understand how the SKA will advance our understanding of planet formation. The project has two main themes, each of which can be explored depending on the interests of the candidate: 1) Growing pebbles into planets: Assembling a young planet involves the growth of micron-sized dust to centimetre sized 'pebbles', and the SKA will be uniquely sensitive to emission from these pebbles in protoplanetary discs. Combining hydrodynamic models of protoplanetary discs and growing planets, you will simulate the growth and evolution of dust grains. You will characterise how planets sculpt the distribution of pebbles, and predict how the SKA will observe discs at different evolutionary stages. 2) Pathways of prebiotic molecules to planets: Molecules important for key biological processes here on Earth ('prebiotic') are detected throughout interstellar space, but their abundance and distribution in the vicinity of forming planets remains poorly understood. You will add the required physical and chemical processes to astrochemical disc models to reproduce the latest observations of large molecules in discs. Armed with these models, you will predict the optimal targets, molecules and transitions to observe with SKA to uncover the prebiotic content of protoplanetary discs.