Exploring the Effect of Planet-Disk Interaction on Exoplanetary Atmospheres

系外行星大气的组成可以解释行星的形成历史。在围绕着年轻恒星的旋转的气体和尘埃盘中，尘埃颗粒凝结成几个地球质量大小的岩石，这些巨大的岩石通过引力吸引周围的气体形成大气层。颗粒和气体的化学成分预计会随着位置的变化而剧烈变化，这取决于圆盘的结构。描述行星的元素比例可以告诉我们行星是在圆盘的哪个位置聚集起来的。这样的推断需要对一个圆盘上不同位置的固态和气态元素丰度的变化有扎实的了解。目前最先进的技术是通过演化盘面来计算几种挥发性物质（如水和碳质氧化物）的相变位置，而不依赖于其中形成的行星。然而，众所周知，行星会极大地扰乱圆盘，造成空隙，并建立尘埃颗粒的陷阱，内部的气体可能比以前想象的更原始。我们建议量化行星-盘相互作用对系外行星大气的影响。特别是，通过使用开源代码ATHENA++的数值流体力学计算和半解析模型的结合，我们的目标是：1)确定不同大小的尘埃颗粒被行星驱动的压力碰撞捕获的效率；2)追踪这些被困住的尘埃凝聚成次级行星的过程，从而研究多行星动力学对设定盘的组成的影响；3)将这些扰动圆盘中颗粒的运动轨迹转化为挥发物和难熔物质的化学演化；4)建立一个随时间演变的模型，该模型可以反映行星上层大气形成后污染的程度。利用这些见解，我们将填补当前连接原行星盘演化的知识空白，因为它们受到其中出现的行星的干扰，并且可以用新的詹姆斯韦伯太空望远镜和即将到来的太空任务Ariel进行测试的系外行星大气研究的可观察趋势。

Compositions of exoplanetary atmospheres encode the planet's formation history. Within a spinning disk of gas and dust that surround a young star, the dust grains coagulate into rocks as massive as a few Earth masses and these massive rocks build atmospheres by gravitationally attracting the surrounding gas. The chemical composition of both the grains and the gas is expected to change drastically with location, depending on the structure of the disk. Characterizing the elemental ratio of planets can inform where in the disk the planet has assembled. Such inference requires solid understanding of the varying elemental abundance in both solid and gaseous form at different locations of a disk. The current state-of-the-art is to compute the location of phase transitions of several volatile species such as water and carbonaceous oxides by evolving the underlying disk, independent of the planets that form within them. However, planets are known to perturb the disk significantly carving out gaps and establishing traps of dust grains, interior to which the gas may be more pristine than previously thought. We propose to quantify the effect of planet-disk interactions on the exoplanetary atmospheres. In particular, through a combination of numerical hydrodynamic calculations using an open-source code ATHENA++ and semi-analytic models, we aim to 1) determine the efficiency at which the dust grains of varying sizes could be trapped by planet-driven pressure bumps; 2) track the coagulation of these trapped dust into secondary planets thereby investigating the effect of multi-planetary dynamics in setting the disk composition; 3) translate the trajectory of grains in these perturbed disks into chemical evolution of volatiles and refractory species; and to 4) build a model that evolves in time the degree of post-formation pollution in the upper atmospheres of planets. Using these insights, we will fill in the current knowledge gap connecting the evolution of protoplanetary disks as they are perturbed by the planets that emerge within them with the observable trends in studies of exoplanetary atmospheres that can be tested with the new James Webb Space Telescope and the upcoming space mission Ariel.