# Princeton University Extrasolar Planet Discussion Group

## Resonant Excitation of Planetary Eccentricity due to a Dispersing Eccentric Protoplanetary Disk: A New Mechanism of Generating Large Planetary Eccentricities

I will present a new mechanism of generating large planetary eccentricities. This mechanism applies to planets within the inner cavities of their companion protoplanetary disks. A massive disk with an inner truncation may become eccentric due to non-adiabatic effects associated with gas cooling, and can retain its eccentricity in long-lived coherently-precessing eccentric modes; as the disk disperses, the inner planet will encounter a secular resonance with the eccentric disk when the planet and the disk have the same apsidal precession rates; the eccentricity of the planet is then excited to a large value as the system goes through the resonance. In this talk, I will discuss how disks may spontaneously become eccentric through eccentric mode instability. Then, I will present an approximate secular dynamics model to calculate the long-term evolution of the "planet + dispersing eccentric disk" system. Our calculations find that the planet can attain a large eccentricity (between 0.1 and 0.6) in this model. This eccentricity excitation can be understood in terms of the mode conversion (avoided crossing'') phenomenon associated with the evolution of the "planet + disk" eccentricity eigenstates.

### Date & Time

November 28, 2022 | 12:00pm – 1:00pm

### Location

Zoom and Peyton Dome Rm, Princeton University

Jiaru Li

### Speaker Affiliation

Cornell University