Migration and Survival of Exoplanets near Magnetized Young Stars

Cornell University, Ithaca NY

Investigators

Abstract

A research investigation conducted by a team from Cornell University will simulate the orbital migration of planets under the influence of a host star's magnetic field. Observations present an important problem: large, gaseous planets that are thought to form far from their host stars are often found to orbit very close to their host stars. It is thought that after forming, gas planets migrate towards their host stars by losing angular momentum to friction within a disk of gas and dust. However, it is not understood why these planets do not fall into the star. An important problem in the science of planets today is understanding how they survive in such close proximity to their host stars. This team will investigate through supercomputer simulations what role the stellar magnetic field plays in the survival and orbital distribution of planets. They will also develop a new tabletop astronomy exhibit at the local Sciencenter. The Exhibit will educate the public about the properties of magnets and the magnetic fields of the Earth and Sun, and it will prepare them for the total Solar eclipse of 2024, which will be visible near Ithaca, NY. One graduate student will be actively involved in the modeling of planetary orbits and in explaining science to the public at the Sciencenter. Migration of planets in the vicinity of rotating magnetized stars will be studied in global numerical simulations. The investigation will advance understanding of the role that young magnetized stars play in the migration and survival of exoplanets. Specifically, they will (1) investigate the migration and survival of planets inside magnetospheric cavities, taking into account their interaction with the inner disk; (2) investigate migration and trapping of low-mass planets at disk-cavity boundaries due to corotation torque, and (3) study whether interactions of exoplanets with waves in their inner disks can change eccentricities and inclinations of their orbits. The investigation will use three-dimensional magneto-hydrodynamic codes: the first a code in cylindrical coordinates, which incorporates mesh refinement, and secondly the Cubed Sphere code, which has been used extensively in the past for modeling accretion onto magnetized stars. Both codes include a planetary module that calculates the orbits of planets. 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.