In Situ Formation of Short Period Terrestrial Planets

华盛顿大学的一组科学家将对其他恒星周围岩石行星的形成进行计算机模拟。我们太阳系中的岩石行星是由小得多的天体形成的，这一想法解释了太阳系的许多特征。他们将调查同样的想法是否能成功地解释围绕其他恒星发现的行星系统的形成。他们的结果将解决我们自己的太阳系是否在其形成过程中是异常值的问题。这项研究将集中在距离低质量恒星非常近的行星系统，这是已发现的最常见的行星系统类型。这一项目将让大学生在高性能计算和大数据处理方面获得经验。其中一些工作将在参加华盛顿大学天文学专业预科项目(PreMAP)的本科生的小项目中完成。PreMAP为STEM中代表性不足的学生提供了天文学方面的研究机会。到目前为止，具有紧密堆积的内行星的行星系统(STIPS)是在统计上表现最好的系外行星系统类型，使它们成为行星形成理论的极好试验台。然而，旨在复制我们太阳系结构的行星形成模型通常无法解释海王星看似奇异的种群。类地行星形成的标准模型的一个关键组成部分是从大约千米大小的天体增长到完整大小的行星，在这种体制下，物理学由引力相互作用和天体之间的碰撞主导。该团队将使用最近增强的、高度可伸缩的粒子代码来跟踪行星小星在短周期轨道上的演化，因为它们在引力作用下相互作用并发生碰撞。这些模拟的结果随后将被传递到辛粒子代码，以跟踪行星形成的后期阶段数百万次的动力学时间。利用原行星盘化学模型激发的行星微小成分，将预测产生的类地行星的组成，从而能够用詹姆斯·韦伯空间望远镜对STIPS的大气组成进行未来观测，以验证或证伪原位形成的可能性。此外，还将考虑外部巨星在吸积过程中的引力影响，这可能提供从类地行星的轨道和组成属性推断未被检测到的巨星存在的方法。该奖项反映了美国国家科学基金会的法定任务，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

A team of scientists at the University of Washington will perform computer simulations of the formation of rocky planets around other stars. The idea that rocky planets in our own Solar System were formed from much smaller bodies explains many features of the Solar System. They will investigate whether this same idea can successfully explain the formation of the planetary systems found around other stars. Their results will address whether our own Solar System is an outlier in how it formed. The study will focus on the systems of planets very close to low mass stars, which are the most common of type of planetary system discovered. This program will allow university students to gain experience in high performance computing and the handling of “big data”. Some of the work will be done in small projects for undergraduate students participating in the University of Washington's Pre-Major in Astronomy Program (PreMAP). PreMAP provides under-represented students in STEM with research opportunities in astronomy.To date, planetary Systems with Tightly-packed Inner Planets (STIPs) are the most statistically well-represented type of exoplanetary system, making them an excellent testbed for planet formation theories. However, planet formation models designed to reproduce the structure of our own Solar System typically fail to explain the seemingly exotic population of STIPs. A key component of the standard model of terrestrial planet formation is the growth from approximately kilometer size bodies to full sized planets, a regime where the physics is dominated by gravitational interactions and collisions between bodies. The team will use a recently enhanced, highly scalable particle code to follow the evolution of planetesimals on short period orbits as they interact gravitationally and collide. The results from these simulations will then be passed to a symplectic particle code to follow the late stages of planet formation for many millions of dynamical times. Using planetesimal compositions motivated by protoplanetary disk chemistry models, compositions of the terrestrial planets that result will be predicted, allowing future observations observations of the atmospheric composition of STIPs with James Webb Space Telescope to validate or falsify the possibility of in situ formation. Additionally, the gravitational influence of an outer giant companion during the accretion process will be considered, which may provide ways to infer the presence of an undetected giant companion from the orbital and compositional properties of the terrestrial planetsThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.