Dust grain-size distributions and extinction in the Milky Way, large magellanic cloud, and small magellanic cloud

被引:2075
作者
Weingartner, JC
Draine, BT
机构
[1] Princeton Univ, Dept Phys, Princeton, NJ 08544 USA
[2] Univ Toronto, CITA, Toronto, ON M5S 3H8, Canada
[3] Princeton Univ Observ, Princeton, NJ 08544 USA
基金
美国国家科学基金会;
关键词
dust; extinction; ISM : clouds;
D O I
10.1086/318651
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
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 R-V. 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 R-V and b(C), 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.
引用
收藏
页码:296 / 309
页数:14
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