Dust grain-size distributions and extinction in the Milky Way, large Magellanic Cloud, and small Magellanic Cloud

Joseph C. Weingartner, B. T. Draine

Research output: Contribution to journalArticle

1504 Scopus citations

Abstract

We construct size distributions for carbonaceous and silicate grain populations in different regions of the Milky Way, LMC, and SMC. The size distributions include sufficient very small carbonaceous grains (including polycyclic aromatic hydrocarbon molecules) to account for the observed infrared and microwave emission from the diffuse interstellar medium. Our distributions reproduce the observed extinction of starlight, which varies depending on the interstellar environment through which the light travels. As shown by Cardelli, Clayton, and Mathis in 1989, these variations can be roughly parameterized by the ratio of visual extinction to reddening, Rv. We adopt a fairly simple functional form for the size distribution, characterized by several parameters. We tabulate these parameters for various combinations of values for Rv and bc, the C abundance in very small grains. We also find size distributions for the line of sight to HD 210121 and for sight lines in the LMC and SMC. For several size distributions, we evaluate the albedo and scattering asymmetry parameter and present model extinction curves extending beyond the Lyman limit.

Original languageEnglish (US)
Pages (from-to)296-309
Number of pages14
JournalAstrophysical Journal
Volume548
Issue number1 PART 1
DOIs
StatePublished - Feb 10 2001

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Dust, extinction
  • ISM: clouds

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