CAREER: The True Mass-Radius-Period Distribution of Small Exoplanets

当今系外行星研究的主要目标之一是了解宇宙中行星的质量分布。精确的质量将有助于建立质量/密度与轨道半径的关系，并在可居住区域识别类地岩石行星。这些进展代表了理解行星形成过程的重要新途径。这里提出的工作将挖掘开普勒数据并使用新技术来确定开普勒航天器观测到的所有706个多行星（多行星）系统的行星质量。现在，可以估计大约10%的样本的质量：在这些系统中观测到的瞬变时间变化（TTVs）。这项工作的结果将指导未来对类地行星的观测和搜索，无论是用太空望远镜，如JWST，还是地面望远镜，如未来的us - elt。拓展和教育工作包括指导至少五名来自代表性不足群体的学生，开发基于研究的教育资源，开发与天文学相关的动画动图库，并支持在OpenStax天文学教科书中开发关于系外行星的章节。该团队将使用他们公开的光动力多行星模型（PhoDyMM）对所有706个开普勒多凌日系统（mts）进行分析。光动力学模型包括行星系统的完整n体动力学演化，但直接适合开普勒光度光曲线本身。到目前为止，大多数对mts的分析都依赖于凌日时间变化（TTVs），因为多颗行星相互牵拉，会略微推迟或加速预期的凌日。完整的光动力学分析只应用于706颗已知开普勒mss中的20颗。这项技术还利用了开普勒短节奏数据，而传统的TTV分析通常会忽略这些数据。除了发现许多超级地球和其他更大的行星的质量外，研究小组还希望对最小的系外行星进行至少50次新的质量测定，目前的方法还无法做到这一点。这种方法有望探测到质量分布低端的新行星。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

One of the chief goals in exoplanet research today is to understand the mass distribution of planets in the universe. Having accurate masses will help establish mass/density vs. orbital radius relationships, and to identify rocky Earth-like planets in the habitable zone. These advances represent an important new avenue to understanding planetary formation processes. The work proposed here will mine the Kepler data and use new techniques to identify masses of planets in all 706 multi-transit (multi-planet) systems observed by the Kepler spacecraft. Right now, masses can be estimated for about 10% of this sample: the systems in which transit-time variations (TTVs) are observed. The results of this work will guide future observations and searches done for Earth-like planets, be they done with space-based telescopes, such as JWST, or ground-based telescopes, such as the future US-ELTs. Outreach and education efforts include the mentoring of at least five students from under-represented groups, the development of research-based education resources, the development of a library of animated gifs related to astronomy, and supporting development of a chapter on exoplanets in an OpenStax astronomy textbook.The team will conduct an analysis of all 706 Kepler multi-transiting systems (MTSs) using their publicly-available PhotoDynamical Multi-planet Model (PhoDyMM). A photodynamical model includes the full n-body dynamical evolution of a planetary system, but fits directly to the Kepler photometric lightcurve itself. Until now, most analyses of MTSs have relied upon transit timing variations (TTVs) as the multiple planets tug each other around, slightly delaying or accelerating expected transits. Full photodynamical analysis has been applied to only 20 of the 706 known Kepler MTSs. This technique also makes use of the Kepler short cadence data, which traditional TTV analysis typically ignores. In addition to finding masses for many super-Earths and other larger planets, the team expects to make at least 50 new mass determinations of the smallest exoplanets, until now inaccessible to current methods. This method has the promise to detect new planets at the lower end of the mass distribution.This 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.