Galactic dust evolution with rapid dust formation in the interstellar medium due to hypersonic turbulence

Understand

Turbulence can significantly accelerate the growth of dust grains by accretion of molecules.

• For dust dynamically coupled to the gas, the growth rate scales with the square of the Mach number, which means that the growth timescale can easily be reduced by more than an order of magnitude.
• The limiting timescale is therefore rather the rate of molecular cloud formation, which means that dust production in the ISM can rapidly reach the levels needed to explain the dust masses observed at high redshifts.
• Thus, turbulence may be the solution to the replenishment problem in models of dust evolution in high-redshift galaxies and explain the dust masses seen at $z = 7 - 8$.