2019MNRAS.486.1681S

With the use of numerical models, we investigate whether Mean Motion Resonances (MMRs) with nearby moons to the J1407b ring system were the cause of the observed 0.0267 au wide gap located at 0.4 au. Only one location of a moon at 0.63 au (corresponding to a 2:1 MMR) was found to form a gap at 0.4 au over short time periods of < 100 yr. However, the proximity of a low mass moon (0.08 M⊕) caused significant scattering of the outer ring edge at 0.6 au along with the formation of an additional gap at the 3:2 MMR (0.485 au), which is not consistent with observations. Further models with moons located at MMRs 3:1, 4:1, 7:3, and 5:3 failed to form gaps at 0.4 au for time periods < 100 yr. Instead, gaps were formed in the ring at 3:2 and 2:1 MMRs which resulted in gaps at radial locations between 0.44 0.56 au. Additionally, gaps also take longer than one orbital period of J1407b about the primary to form. Given that J1407b is on a highly eccentric orbit and is thought to strongly perturb the ring at apocentre it appears unlikely that gaps form due to MMRs with nearby moons as opposed to embedded moons. Including an appropriate total mass of the ring equal to Earth a dampening effect was witnessed on the gap formation process, causing an increase in the time required to open a gap due to MMRs. Therefore, we conclude the observed gap at 0.4 au is unlikely to be caused by MMRs with nearby moons.