Dynamical Evolution of Planetary Systems in Star Clusters

星团中行星系统的动力学演化

• 批准号: 1302765
• 负责人: Aaron Geller
• 金额: $ 8.9万
• 依托单位: Geller Aaron M
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1302765&HistoricalAwards=false
• 关键词: Dynamical; Evolution; Planetary; Systems; Star

Dr. Aaron Geller is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at Northwestern University. The fellow's project involves exoplanets. Today, astronomers are discovering a rich panoply of exoplanets in our Galaxy. Many of these exoplanets are in multi-planet systems. Some show surprisingly different characteristics from our own Solar System that pose serious problems for standard isolated planet formation theories. Strong evidence indicates that the majority of stars form in clusters, many of which dissolve within the age of the Universe. Therefore, many of the exoplanets observed today---in stars clusters and the field of the Galaxy---may have been born inside star clusters and subjected to past perturbations from nearby stars. Understanding how stellar encounters within this birth environment affect the dynamical evolution of planetary systems is paramount to interpreting the characteristics of all the newly discovered exoplanets and how these relate to the planet formation epoch. To address these important questions, the fellow work with a team of experts to complete development of the first computer code to self-consistently simulate the dynamical evolution of multi-planet systems in realistic star clusters. Dr. Geller and collaborators have already completed a pilot code demonstrating the feasibility of the most critical and innovative components, and the full code will be completed early in the first year of the fellowship. The fellow will then use this code to model nine open star clusters, including four in the Kepler field that have been surveyed comprehensively for transiting exoplanets. Each cluster will be modeled with multiple different initial planet populations to cover the range in characteristics of observed exoplanets. The simulations will be analyzed, accounting for the unique sensitivity limits of each transit survey, and the results will be compared directly with the observations. This project will reveal---for the first time self-consistently---how stellar encounters within star clusters of a wide range in age, density, mass, etc., influence the dynamical evolution of multi-planet systems including those like our Solar System and how the characteristics of exoplanets observed today in both clusters and the field may have been modified in the past by their birth environment.The broader impacts of this project include a significant educational component. The fellow will undertake a program of educational outreach in partnership with the Northwestern's NSF-funded GK-12 and CE21 programs to develop, test, and disseminate about 15 high school lesson plans based on the scientific research of this project. The fellow will work directly with a Northwestern graduate student to develop around five classroom-tested high school lesson plans each year. To supplement the lesson plans, the fellow will also develop a web-based student-friendly interface to both analyze the products of the proposed simulations and to allow students to run simulations of their own. During years 2 and 3 the fellow will integrate these lesson plans into teacher professional development workshops, which the PI will co-lead. Through these workshops, the fellow will train about 20 Chicago Public School and area teachers to use his lesson plans, thereby reaching about 2000 students with his curricular materials by the end of the fellowship. Both the GK-12 and CE21 programs are well established at Northwestern University and have been running successfully for years. This is a natural and mutually beneficial partnership that will help train the fellow for a future career teaching computational thinking methods in undergraduate physics and astronomy courses.

Aaron Geller博士被授予NSF天文学和天体物理学博士后奖学金，在西北大学开展一项研究和教育计划。这个家伙的项目涉及系外行星。今天，天文学家在我们的银河系中发现了丰富的系外行星。其中许多系外行星位于多行星系统中。其中一些显示出与我们太阳系惊人的不同特征，这对标准的孤立行星形成理论构成了严重的问题。强有力的证据表明，大多数恒星是以星团形式形成的，其中许多星团在宇宙年龄内溶解。因此，今天观测到的许多系外行星-在星团和银河系的场中-可能是在星团内部诞生的，并受到附近恒星过去的扰动。了解在这个诞生环境中的恒星相遇如何影响行星系统的动力学演化，对于解释所有新发现的系外行星的特征以及这些特征与行星形成时期的关系至关重要。为了解决这些重要的问题，这位研究员与一个专家团队合作，完成了第一个计算机代码的开发，以自我一致地模拟现实星团中多行星系统的动态演化。盖勒博士和合作者已经完成了一项试验代码，展示了最关键和最具创新性的组件的可行性，完整的代码将在奖学金的第一年初完成。然后，这位研究员将使用这个代码对九个开放星团进行建模，其中包括开普勒领域中的四个星团，这些星团已经为凌日系外行星进行了全面的调查。每个星团将用多个不同的初始行星群进行建模，以涵盖所观测到的系外行星的特征范围。将对模拟进行分析，考虑到每个经纬仪调查的唯一灵敏度限制，并将结果直接与观测值进行比较。这个项目将首次自始至终地揭示-在年龄、密度、质量等大范围的星团内恒星相遇如何影响包括我们太阳系在内的多行星系统的动态演化，以及今天在星团和磁场中观察到的系外行星的特征在过去如何被它们的诞生环境所改变。这个项目的更广泛的影响包括一个重要的教育组成部分。该研究员将与西北大学NSF资助的GK-12和CE21计划合作开展一项教育推广计划，以此项目的科学研究为基础，开发、测试和传播约15个高中教案。这位研究员将直接与西北大学的一名研究生合作，每年制定大约五个经过课堂测试的高中教案。为了补充课程计划，该研究员还将开发一个基于网络的学生友好界面，以分析拟议模拟的产品，并允许学生运行他们自己的模拟。在第二年和第三年，该研究员将把这些课程计划整合到教师专业发展研讨会中，由PI共同领导。通过这些研讨会，这位研究员将培训大约20名芝加哥公立学校和地区教师使用他的教案，从而在奖学金结束时向大约2000名学生提供他的课程材料。GK-12和CE21课程在西北大学都有良好的基础，并已成功运行多年。这是一种自然和互惠互利的合作伙伴关系，将有助于为未来的职业生涯培训研究员，在本科物理和天文学课程中教授计算思维方法。