The Fundamentally Different Dynamics of Dust and Gas in Molecular Clouds

Understand

We study the behavior of large dust grains in turbulent molecular clouds (MCs).

• In primarily neutral regions, dust grains move as aerodynamic particles, not necessarily with the gas.
• We therefore directly simulate, for the first time, the behavior of aerodynamic grains in highly supersonic, magnetohydrodynamic turbulence typical of MCs.
• We show that, under these conditions, grains with sizes a >0.01 micron exhibit dramatic (exceeding factor ~1000) fluctuations in the local dust-to-gas ratio (implying large small-scale variations in abundances, dust cooling rates, and dynamics).