Interstellar Dust
Abstract
In the interstellar medium of the Milky Way, certain elements -- e.g., Mg, Si, Al, Ca, Ti, Fe -- reside predominantly in interstellar dust grains. These grains absorb, scatter, and emit electromagnetic radiation, heat the interstellar medium by photoelectric emission, play a role in the ionization balance of the gas, and catalyze the formation of molecules, particularly H2. I review the state of our knowledge of the composition and sizes of interstellar grains, including what we can learn from spectral features, luminescence, scattering, infrared emission, and observed gas-phase depletions. The total grain volume in dust models which reproduce interstellar extinction is significantly greater than estimated from observed depletions. Dust grains might reduce the gas-phase D/H ratio, providing an alternative mechanism to explain observed variations in the gas-phase D/H ratio in the local interstellar medium. Transport in dust grains could cause elemental abundances in newly-formed stars to differ from interstellar abundances.
Cite
@article{arxiv.astro-ph/0312592,
title = {Interstellar Dust},
author = {B. T. Draine},
journal= {arXiv preprint arXiv:astro-ph/0312592},
year = {2007}
}
Comments
18 pages, 7 figures. To appear in "Carnegie Observatories Astrophysics Series, Vol. 4: Origin and Distribution of the Elements", ed. A. McWilliam and M. Rauch (Cambridge: Cambridge Univ. Press)