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arXiv 0903.1658astro-ph.GAastro-ph.CO
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Interstellar Dust模型及其演化含义

Interstellar Dust Models and Evolutionary Implications

B. T. Draine

摘要:

星际消光和偏振的波长依赖性,补充观测到的元素丰度和星光加热的尘埃红外发射光谱,强烈约束尘埃模型。一个尘埃模型,似乎是与观测相一致。为了重现观测到的灭绝,该模型消耗了大量的星际Mg,Si和Fe(在无定形硅酸盐中),以及相当大一部分的C(在碳质材料中),并调整了尺寸分布和排列以匹配观测结果。星际颗粒的组成、结构和尺寸分布是恒星流出物中的尘埃注入星际介质(ISM)的结果,随后是星际颗粒的破坏、生长、凝聚和光处理。这些不太清楚的过程之间的平衡是ISM中固体物质混合的原因。大多数存在于弥漫ISM中的星际颗粒物质必须在ISM中生长。因此,构成星际尘埃主体的无定形硅酸盐和碳质物质一定是在紫外线辐射存在下颗粒生长的结果。在高z系统中的尘埃,如J1148+5251,也主要是在ISM中产生的,超新星产生的尘埃只占总尘埃质量的一小部分。

英文摘要:

The wavelength dependences of interstellar extinction and polarization, supplemented by observed elemental abundances and the spectrum of infrared emission from dust heated by starlight, strongly constrain dust models. One dust model that appears to be consistent with observations is presented. To reproduce the observed extinction, the model consumes the bulk of interstellar Mg, Si, and Fe (in amorphous silicates), and a substantial fraction of C (in carbonaceous material), with size distributions and alignment adjusted to match observations. The composition, structure, and size distribution of interstellar grains is the result of injection of dust from stellar outflows into the interstellar medium (ISM), followed by destruction, growth, coagulation, and photoprocessing of interstellar grains. The balance among these poorly-understood processes is responsible for the mix of solid material present in the ISM. Most interstellar grain material present in the diffuse ISM must be grown in the ISM. The amorphous silicate and carbonaceous materials that form the bulk of interstellar dust must therefore be the result of grain growth in the presence of ultraviolet radiation. Dust in high-z systems such as J1148+5251 is also produced primarily in the ISM, with supernova-produced dust contributing only a small fraction of the total dust mass.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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