1D accretion discs around eccentric planets: observable near-infrared variability

TL;DR

This study models circumplanetary discs around eccentric planets to predict near-infrared variability detectable by JWST, providing insights into planet-disc interactions and eccentricity growth.

Contribution

It introduces 1D viscous disc models around eccentric planets to assess JWST detectability of infrared variability, linking disc properties to planetary orbital evolution.

Findings

Variability detectable by JWST for certain disc viscosities and eccentricities.

Disc accretion rates above 10^{-7} solar masses per year are necessary.

Model limitations impact the interpretation of observational prospects.

Abstract

I present the results of 1D models of circumplanetary discs around planets on eccentric orbits. I use a classical viscous heating model to calculate emission fluxes at the wavelengths targeted by the NIRCam instrument on JWST, and compare the variability of this signal with the published NIRCam sensitivity specifications. This variability is theoretically detectable by JWST for a sufficiently viscous disc ($\alpha \sim 10^{-2}$) around a sufficiently eccentric planet ($e \sim 0.1-0.2$) and if the circumplanetary disc accretes material from its parent disc at a rate $\dot{M} \gtrsim 10^{-7}\, \mathrm{M}_{\odot}\,\mathrm{yr}^{-1}$. I discuss the limitations of the models used, and the implications of the result for probing the effectiveness of disc interactions for growing a planet's orbital eccentricity.