The Search for Disk Perturbing Planets Around the Asymmetrical Debris Disk System HD 111520 Using REBOUND

TL;DR

This study uses simulations to infer the presence and properties of potential planets shaping the asymmetrical debris disk around HD 111520, demonstrating how disk structures can reveal unseen planetary companions.

Contribution

First detailed modeling of the HD 111520 debris disk using REBOUND to constrain possible planet characteristics based on observed asymmetries.

Findings

A ~1 Jupiter mass eccentric planet at >200 au can explain most disk features.

A second eccentric planet inside 50 au may account for surface brightness asymmetry.

Current models cannot reproduce the observed brightness asymmetry, indicating additional mechanisms are involved.

Abstract

Debris disks, which are optically thin, dusty disks around main sequence stars, are often found to have structures and/or asymmetries associated with planet-disk interactions. Debris disk morphologies can hence be used as probes for planets in these systems which are unlikely to be detected with other current exoplanet detection methods. In this study we take a look at the very asymmetrical debris disk around HD 111520, which harbours several signs of perturbation such as a ``fork"-like structure in the NW, as well as a 4$^{\circ}$ warp from the midplane on either side of the disk. We simulate the complicated disk morphology using the code REBOUND, with the goal of constraining the possible mass and orbit of the planet responsible for the observed structures. We find that a $\sim$1 M$_{jup}$, eccentric planet that is inclined relative to the disk and has a semi-major axis of $\gtrsim$200 au, is able to reproduce the majority of disk features including the warp, fork and radial extent asymmetry. To create the surface brightness asymmetry, a second eccentric planet is required inside the disk inner edge (50 au), although we are unable to produce the 2 to 1 brightness asymmetry observed, suggesting that a second mechanism may be required. Our work demonstrates how debris disk morphologies alone can be used to learn more about the architecture and evolution of a system as a whole, and can provide planet constraints to determine potential targets for current/future instruments such as JWST/NIRCam and GPI 2.0.