An Etymological Dictionary of Astronomy and Astrophysics
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The → turbulence phenomenon involving relatively smaller physical volumes compared to → macroturbulence. In stellar atmospheres, it is a bulk gas motion with a characteristic size less than the local photon → mean free path. Microturbulence is one of the most significant mechanisms that can cause → line broadening in the stellar spectrum. The presence of microturbulence de-saturates strong lines and increases their → equivalent widths. Microturbulence in → hot stars brings about gas motions with velocities 0-20 km s^-1. A physical connection may exist between microturbulence in hot star atmospheres and a subsurface → iron convection zone. Microturbulence may also be at the origin of → wind clumping in hot stars.

→ micro-; → turbulence.