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观点解释了太阳系的许多特征。 他们将研究同样的想法是否可以成功地解释其他恒星周围行星系统的形成。他们的结果将解决我们自己的太阳系是否是一个异常值。这项研究将侧重于非常接近低质量恒星的行星系统，这是发现的最常见的行星系统类型。该计划将使大学生获得高性能计算和处理“大数据”的经验。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领域的学生提供了天文学研究机会。迄今为止，具有紧密堆积的内部行星的行星系统（STIPs）是统计上最具代表性的系外行星系统类型，使其成为行星形成理论的绝佳测试平台。然而，旨在重现我们太阳系结构的行星形成模型通常无法解释STIPs看似奇异的人口。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到全尺寸行星的生长，这是一个物理学由引力相互作用和天体之间的碰撞主导的区域。该团队将使用最近增强的，高度可扩展的粒子代码来跟踪短周期轨道上的微行星在引力相互作用和碰撞时的演化。然后，这些模拟的结果将被传递到辛粒子代码中，以跟踪行星形成的后期阶段数百万个动力学时间。使用由原行星盘化学模型激发的星子成分，将预测产生的类地行星的成分，允许未来用詹姆斯·韦伯太空望远镜观测STIPS的大气成分，以验证或证伪原位形成的可能性。此外，在吸积过程中，一个外巨行星的引力影响将被考虑，这可能会提供一些方法，从地球行星的轨道和成分特性推断出一个未被发现的巨行星的存在。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

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.