Spin-Orbit Misalignment in S-Type Binaries

Poster for ERES 2021 Virtual Conference.

Abstract:

In the early stages of their lives, stars very often are part of a binary pair or a higher order multiple. Such a prevalence of binary systems means that they should be included in discussions of the evolution of exoplanetary systems. We utilize a hybrid symplectic integrator to evolve a system of s-type planets in a co-planar binary that is in turn evolved through an embedded cluster environment. In a non-negligible number of cases, the cluster perturbs the binary companion onto an eccentric orbit, causing an orbital instability in the 4 gas giants that we place around the primary. In addition to characterizing these instabilities, we also look at the changes in orbital architecture for the planetary systems that have undergone a loss of 1 or more planets. We find that there is a marked difference in the eccentricity and spin-orbit angle distributions of planetary systems that have undergone an instability compared to those that remain stable for the duration of our 10 Myr simulations. The preference for these unstable systems to occupy higher spin-orbit angles than their stable counterparts indicates that interactions with a binary companion driven by a cluster environment could be a source for misaligned exoplanets.