Chemistry in planet-forming regions revealed by ALMA

阿塔卡马大型毫米/亚毫米阵列（阿尔马）是智利的一个望远镜，以毫米波长观测宇宙。阿尔马具有观测行星形成尺度上冷尘埃和分子气体发射的分辨率和灵敏度。这使我们能够探测附近恒星周围的行星形成环境，其大小与太阳系相似。阿尔马最近的观测揭示了在附近年轻恒星周围的尘埃盘中几乎无处不在的尘埃亚结构，其中尘埃被引导到同心尘埃环和不对称的漩涡中。这种尘埃结构的一个可能来源是盘内仍在形成的行星。利兹研究人员最近参与的一项名为“行星形成尺度上的阿尔马分子”或MAPS的阿尔马大型计划首次成像了太阳系尺度上行星形成的化学过程（www.alma-maps.info）。这些数据揭示了丰富的化学多样性，观察到的化学亚结构通常与尘埃亚结构不一致。目前还不清楚为什么行星盘具有如此多样的化学成分，但这可能是由于尘埃、辐射、化学和物质传输之间复杂的相互作用。确定行星盘中化学亚结构的起源需要开发新的原行星盘模型，将所有这些重要的物理效应结合起来。该项目将开发新的磁盘化学模型，包括尘埃演化和子结构，径向运输和混合的影响，由目前的理论驱动的尘埃子结构在磁盘中的起源。这些模型将被用来模拟观测结果，直接与MAPS阿尔马大型计划的结果进行比较，并产生诊断套件，用于激励未来的阿尔马提案。

The Atacama Large Millimeter/submillimeter Array (ALMA) is a telescope in Chile that observes the universe at millimeter wavelengths. ALMA has the resolution and sensitivity to observe emission from cold dust and molecular gas on planet-forming scales. This allows us to probe the planet-building environment around nearby stars on size scales similar to the Solar System. Recent observations with ALMA have revealed the almost ubiquitous presence of dust substructure in disks around nearby young stars, in which the dust has been shepherded into concentric dust rings and asymmetric vortices. One of the proposed origins of this dust structure is the presence of still-forming planets within the disk.A recent ALMA Large Program involving Leeds' researchers, titled "Molecules with ALMA on Planet-forming Scales" or MAPS, imaged for the first time, the chemistry of planet formation on Solar System size scales (www.alma-maps.info). These data revealed a wealth of chemical diversity, with observed chemical sub-structure usually not coincident with dust sub-structure. It is still not understood why disks exhibit such chemical diversity but it is likely due to the complex interplay between dust, radiation, chemistry, and transport of material.Determining the origin of chemical sub-structure in disks requires the development of new models of protoplanetary disks that incorporate all of these important physical effects. This project will develop new models of disk chemistry that include the effects of dust evolution and sub-structure, radial transport, and mixing, motivated by current theories on the origin of dust sub-structure in disks. These models will be used to simulate observations to directly compare with the results from the MAPS ALMA Large Program, and to produce suites of diagnostics that will be used to motivate future ALMA proposals.