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Session 16 - Interstellar Grains, PAH's and the Interstellar Bands.
Display session, Monday, January 13
Metropolitan Ballroom,

[16.03] Grain Alignment and Crossover Events

A. Lazarian, B. Draine (Princeton Univ. Obs.)

We discuss the dynamics of grains subjected to uncompensated torques. In particular, we discuss grain dynamics when a grain spins down and goes through a crossover. We calculate the degree of correlation for the grain angular momentum before and after a crossover and quantitatively discuss how this correlation affects grain alingment. We show that thermal fluctuations within the grain material limit the degree to which the grain angular momentum is coupled with the grain principal axis of maximal inertia. We find that this imperfect coupling plays a critical role during crossovers and increases substantially the efficiency of paramagnetic alignment. We also discuss the role of crossovers for mechanical alignment and for the alignment by radiative torques.

Program listing for Monday