Radiating Bondi Flows II: Giant Planet Accretion Models

TL;DR

This paper investigates how radiative feedback from forming giant planets significantly suppresses gas accretion rates compared to classical models, especially within 10 AU, affecting planet formation theories.

Contribution

It quantifies radiative feedback effects on giant planet accretion, providing a more realistic model that accounts for heating and suppression of accretion rates.

Findings

Accretion suppressed by 1-2 orders of magnitude within 10 AU

Feedback effect is less pronounced for gap-opening planets (~1 order)

Radiative suppression is insensitive to dust opacity, shock efficiency, and planet radius

Abstract

In the core accretion model of giant planet formation, the late stages of runaway growth are regulated by the hydrodynamic infall of gas from the protoplanetary disk. For a subset of planet-disk pairings, this scenario is analogous to the classical Bondi problem, which has motivated a Bondi-like parameterization of accretion in some population synthesis models. Existing models and the associated classical Bondi rate however, are predicated upon an adiabatic equation of state. In reality, the planet and its associated accretion shock supply a luminosity that substantially heats the accretion flow. In Paper I of this series, we demonstrate that such radiative feedback can dramatically suppress accretion by orders of magnitude. Here we quantify this effect under realistic planet-forming conditions. We find that for planets forming in an unperturbed disk, accretion is suppressed by 1-2 orders of magnitude interior to $\sim 10$ AU. For planets that open a gap, this feedback is less dramatic and the effect is $\sim$ 1 order in magnitude. We investigate the effect of various assumptions regarding dust opacities, shock efficiency, and planet radius and find this radiative suppression mechanism to be fairly insensitive to these effects. We also perform full time-dependent simulations demonstrating that the associated adverse entropy profiles are accurate and stable to convection. A simple and flexible set of open-source tools are provided to incorporate this radiative feedback into existing accretion models and population synthesis frameworks.