Disorientation of Suprathermally Rotating Grains and Grain Alignment Problem

Details Disorientation of Suprathermally Rotating Grains and Grain Alignment Problem Disorientation of Suprathermally Rotating Grains and Grain Alignment Problem

1996-12-19

arxiv.org/abs/astro-ph/9612199v1

Astrophys.J. 487 (1997) 248

Astronomy and Astrophysics

Astrophysics

24 pages, 2 figures, submitted to ApJ, see also http://www.astro.princeton.edu/~library/prep.html

Scientific paper

10.1086/304587

We discuss the dynamics of dust grains subjected to uncompensated torques arising from H_2 formation. In particular, we discuss grain dynamics when a grain spins down and goes through a ``crossover''. As first pointed out by Spitzer & McGlynn (1979), the grain angular momentum before and after a crossover event are correlated, and the degree of this correlation affects the alignment of dust grains by paramagnetic dissipation. We calculate the correlation including the important effects of thermal fluctuations within the grain material. These fluctuations limit the degree to which the grain angular momentum J is coupled with the grain principal axis a_1 of maximal inertia. We show that this imperfect coupling of a_1 with J plays a critical role during crossovers and can substantially increase the efficiency of paramagnetic alignment for grains larger than 10^{-5} cm. As a result, we show that for reasonable choices of parameters, the observed alignment of $a\gtrsim 10^{-5}$ cm grains could be produced by paramagnetic dissipation in suprathermally rotating grains, if radiative torques due to starlight were not present. We also show that the efficiency of mechanical alignment in the limit of long alignment times is not altered by the thermal fluctuations in the grain material.

Affiliated with

Also associated with

No associations

Rating

Disorientation of Suprathermally Rotating Grains and Grain Alignment Problem does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Disorientation of Suprathermally Rotating Grains and Grain Alignment Problem, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Disorientation of Suprathermally Rotating Grains and Grain Alignment Problem will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-31367