Efficient Radiative Transfer in Dust Grain Mixtures
Efficient Radiative Transfer in Dust Grain Mixtures
复制标题
尘埃颗粒混合物中的高效辐射传输
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
Sebastian Wolf
中科院分区：
文献类型：
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作者：
Sebastian Wolf
研究了由具有不同半径和/或化学成分的球形尘埃颗粒组成的尘埃颗粒混合物对星周壳的温度结构和光谱能量分布的影响。与基于代表相应尘埃颗粒混合物平均光学特性的尘埃颗粒参数近似值的结果的比较表明，（1）真实尘埃颗粒混合物的温度色散随着光学深度的增加而大幅减小，向平均尘埃颗粒参数近似值产生的温度分布收敛；（2）如果考虑≥25个颗粒尺寸，所得光谱能量分布的差异不超过10%，这证明了平均参数近似值和迄今为止在其假设下获得的许多结果是合理的。然而，尘埃壳内边界处的尘埃颗粒温度分散可能达到 ≫100 K，因此在化学网络等正确模拟中必须考虑这一点。为了研究几何效应的额外影响，使用 Cotera 等人的模型参数考虑了二维结构——HH 30 星周盘。和伍德等人。在圆盘内部 ~1 AU 内发现了大颗粒到小颗粒温度分布的剧烈反转。
The influence of a dust grain mixture consisting of spherical dust grains with different radii and/or chemical composition on the resulting temperature structure and spectral energy distribution of a circumstellar shell is investigated. The comparison with the results based on an approximation of dust grain parameters representing the mean optical properties of the corresponding dust grain mixture reveal that (1) the temperature dispersion of a real dust grain mixture decreases substantially with increasing optical depth, converging toward the temperature distribution resulting from the approximation of mean dust grain parameters, and (2) the resulting spectral energy distributions do not differ by more than 10% if ≥25 grain sizes are considered, which justifies the mean parameter approximation and the many results obtained under its assumption so far. Nevertheless, the dust grain temperature dispersion at the inner boundary of a dust shell may amount to ≫100 K and therefore has to be considered in the correct simulation of, e.g., chemical networks. In order to study the additional influence of geometrical effects, a two-dimensional configuration—the HH 30 circumstellar disk—was considered, using model parameters from Cotera et al. and Wood et al. A drastic inversion of the large to small grain temperature distribution was found within the inner ~1 AU of the disk.