Exploring the Effect of Planet-Disk Interaction on Exoplanetary Atmospheres

探索行星盘相互作用对系外行星大气的影响

• 批准号: 577027-2022
• 负责人: Lee, EveEJ
• 金额: $ 3.28万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762302
• 关键词: Exploring; Effect; Planet; Disk; Interaction

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.

系外行星大气层的成分编码了行星的形成历史。在围绕年轻星星的气体和尘埃的旋转盘中，尘埃颗粒凝结成质量相当于几个地球质量的岩石，这些巨大的岩石通过引力吸引周围的气体来建造大气。颗粒和气体的化学成分预计会随着位置的变化而急剧变化，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在圆盘中的位置。这样的推论需要对圆盘不同位置固态和气态元素丰度的变化有扎实的理解。目前最先进的技术是计算几种挥发性物质（如水和碳氧化物）的相变位置，方法是通过演化底层磁盘，独立于在其中形成的行星。然而，已知行星会扰动圆盘，显著地雕刻出间隙并建立尘埃颗粒的陷阱，内部的气体可能比以前认为的更原始。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，通过使用开放源代码ATHENA++和半解析模型的数值流体动力学计算相结合，我们的目标是：1）确定不同大小的尘埃颗粒可以被行星驱动的压力隆起捕获的效率; 2）跟踪这些被捕获的尘埃凝结成次级行星，从而研究多行星动力学在设置盘组成中的作用; 3）将这些扰动盘中颗粒的轨迹转化为挥发物和难熔物质的化学演化;以及4）建立一个模型，该模型随时间演化行星上层大气中形成后污染的程度。利用这些见解，我们将填补目前的知识空白，连接原行星盘的演变，因为它们受到行星的扰动，这些行星在它们内部出现，可以用新的詹姆斯韦伯太空望远镜和即将到来的太空使命阿里尔进行测试的系外行星大气研究中观察到的趋势。