Genesis of the Super-Earths

该项目旨在改进一类新行星起源的理论模型，这类行星被称为超级地球。这些天体的半径是地球的1-5倍，虽然我们的太阳系中没有超级地球，但通常可以发现它们绕着其他太阳类型的恒星运行。主要目标是找出是否可以在目前观测到的位置(比地球离太阳更近的距离)形成近距离的超级地球行星，或者它们是否一定形成得更远，然后由于行星系统中其他物体的引力效应而移动到更近的地方。PI和他的团队将使用计算和数值积分技术以及从开普勒航天器数据获得的行星测量来开发和约束超级地球形成的模型。他们将在物理学、行星科学和代码开发方面培训和指导两名研究生和两名博士后研究人员。两名研究生(包括一名代表不足的群体的一名成员)将接受天体物理和地球物理研究方面的培训和指导。该小组将使用各种技术来解决超级地球如何形成这一更大的问题。超级地球岩石/金属核的凝聚历史将使用三组？来自周围行星星云的气体的近似和核心吸积将通过恒星结构的与时间相关的方程的数值积分来模拟。该团队还将使用光电离和流体动力学代码研究行星包层如何经历光蒸发侵蚀。超级地球的多重统计数据将通过N体积分来处理，这些N体积分将用于评估外部木星质量的气体巨星如何动态搅动近距离行星并导致它们合并。

This project aims to improve theoretical models of origins of a new class of planets, known as the Super-Earths. These objects have a radius that is between 1-5 times that of the Earth, and although no Super-Earths reside in our solar system, they may be commonly found orbiting other solar-type stars. The main goal is to find out whether close-in Super-Earth planets can form at the locations they are currently observed (closer than the Earth is to our Sun), or whether they must have formed further out and then moved in closer due to gravitational effects of other objects in the planetary systems. The PI and his team will develop and constrain models of Super-Earth formation using calculations and numerical integration techniques along with planetary measurements obtained from Kepler spacecraft data. They will train and mentor two graduate students and two postdoctoral researchers in physics, planetary science and code development. Two graduate students (including one member of an underrepresented group) will be trained and mentored in astrophysics and geophysics research. The group will use a variety of techniques to address the larger problem of how Super-Earths form. Coagulation histories of Super-Earth rock/metal cores will be calculated using the ?three-groups? approximation, and core-accretion of gas from the surrounding planetary nebula will be modeled by numerical integration of the time-dependent equations of stellar structure. The team will also study how the planetary envelopes undergo photoevaporative erosion using photoionization and hydrodynamic codes. Multiplicity statistics of Super-Earths will be addressed via N-body integrations that will be used to assess how exterior Jupiter-mass gas giants might dynamically stir close-in planets and cause them to merge.