TAPIR Seminar

In person: 370 Cahill -- Attendees joining in person must have a valid Caltech UID.

To Join via Zoom: 864 8902 5566

ABSTRACT: Because planets are thought to form in flat disks of gas and dust around young stars, planetary systems should have nearly coplanar orbits, with the host star spinning in the same direction as the planets' orbits.  Although most planetary systems appear to be coplanar, new observations have uncovered planetary systems with large mutual inclinations, stars spinning in the opposite direction as the orbits of surrounding planets, and planet-forming disks with large misalignments between neighboring rings.  In this talk, we discuss how the dynamics of planets forming in disks can generate mutually inclined planetary systems.  As the planet-forming disk loses mass, the precession rates of planets change with time, forcing the system through a resonance which excites mutual inclinations between forming planets, tilts the host star to the planet's orbital plane, and misaligned neighboring rings within the protoplanetary disk.  Because of the ubiquity of protoplanetary disks with deep cavities thought to be carved by massive planets, we argue inclination excitation during disk-dispersal is a compelling mechanism to explain the mutually-inclined planetary systems observed.