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arXiv · 2306.17218

The distribution of accretion rates as a diagnostic of protoplanetary disc evolution

R. Alexander·G. Rosotti·P. J. Armitage·G. J. Herczeg·C. F. Manara·B. Tabone
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Abstract

We show that the distribution of observed accretion rates is a powerful diagnostic of protoplanetary disc physics. Accretion due to turbulent ("viscous") transport of angular momentum results in a fundamentally different distribution of accretion rates than accretion driven by magnetised disc winds. We find that a homogeneous sample of $\gtrsim$300 observed accretion rates would be sufficient to distinguish between these two mechanisms of disc accretion at high confidence, even for pessimistic assumptions. Current samples of T Tauri star accretion rates are not this large, and also suffer from significant inhomogeneity, so both viscous and wind-driven models are broadly consistent with the existing observations. If accretion is viscous, the observed accretion rates require low rates of disc photoevaporation ($\lesssim$$10^{-9}$M$_{\odot}$yr$^{-1}$). Uniform, homogeneous surveys of stellar accretion rates can therefore provide a clear answer to the long-standing question of how protoplanetary discs accrete.

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R. Alexander, G. Rosotti, P. J. Armitage, G. J. Herczeg, C. F. Manara, B. Tabone. 2023-06-29. The distribution of accretion rates as a diagnostic of protoplanetary disc evolution. https://doi.org/10.1093/mnras%2Fstad1983

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