Genesis of the Super-Earths

点击翻译按钮获取中文摘要

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.