Astronomy and Astrophysics Seminars

Effects of planetesimal scattering on planet pairs near first order mean motion resonances

by Mr. Tuhin Ghosh (DAA, TIFR)

Tuesday, April 6, 2021 from to (Asia/Kolkata)
at Zoom link: ( https://zoom.us/j/91984521667?pwd=ZUo0bTQ4dTYxK1pvWVVZQjRtclZ4UT09 (Meeting ID: 919 8452 1667 Passcode: DAAStud21) )
Description
One surprising observed trend among multi-planet systems is the overabundance and deficit of systems with adjacent planet pairs just wide and narrow of first-order mean motion resonances (MMRs) such as 3:2 and 2:1.  Chatterjee & Ford (2015) showed that the overabundance wide of 2:1 MMR can be explained as a result of dynamical scattering between planet pairs initially trapped into a 2:1 MMR and planetesimals distributed in a disk.  We extend this work to study the effects of planetesimal scattering on the orbits of initially resonant and non-resonant planet pairs with initial period ratios in a large range including both 2:1 and 3:2 MMRs. We adopt initial planet and orbital properties based on the observed adjacent planet pairs, but revise the period ratios (to account for changes in the orbital periods due to planetesimal scattering). Our results show that planetesimal scattering usually increases the orbital period ratios of the planet pairs and pushes planet pairs wide of resonances.  We find that a mix of initially resonant and non-resonant planet pairs, upon a period of planetesimal scattering, can reproduce the observed deficit and over-abundance of systems across 2:1 and 3:2 MMRs at least qualitatively.