PNNL

Abstract

For planets to form in the nebula around a new-born star, they must hurry: Ina few million years or less the star's stellar winds will disperse much of the remaining dust (Briceno, et. al 2001). How do the dust grains stick together fast enough to form gravitationally bound planetsimals? The distinct properties of cryogenic (5-100 K) amorphous water ice, which composes or coats the grains, could be the key. Measurements are presented that show this ice readily acquires persistant macroscopic electric dipoles, strongly enhancing grain-grain adhesion. It is also highly mechanically inelastic (about 10% rebound). Together these explain this efficient sticking.