Large grains can grow in circumstellar discs

TL;DR

This study uses advanced coagulation and fragmentation simulations with a probabilistic collision velocity model to demonstrate that large grains can grow in circumstellar discs, including brown dwarf discs, with growth patterns similar to T Tauri discs.

Contribution

It introduces a physically-motivated collision velocity distribution approach and shows that grain growth to larger sizes is feasible in both T Tauri and brown dwarf discs.

Findings

Growth to larger grain sizes than previous models

Similar growth sizes in scaled-down brown dwarf discs and T Tauri discs

Growth occurs at comparable relative locations in different disc types

Abstract

We perform coagulation & fragmentation simulations to understand grain growth in T Tauri & brown dwarf discs. We present a physically-motivated approach using a probability distribution function for the collision velocities and separating the deterministic & stochastic velocities. We find growth to larger sizes compared to other models. Furthermore, if brown dwarf discs are scaled-down versions of T Tauri discs (in terms of stellar & disc mass, and disc radius), growth at the same location with respect to the outer edge occurs to similar sizes in both discs.