A three-dimensional model of the Orion Nebula
A three-dimensional model of the Orion Nebula
复制标题
猎户座星云的三维模型
DOI：
10.1086/175123
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
C. O’Dell
中科院分区：
文献类型：
--
作者：
Z. Wen;C. O’Dell
我们已经建立了一个几何模型的猎户座星云利用的事实，即大部分的辐射来自一个相对较薄的电离层附近的电离前的巨大分子云OMC-1的近侧的电离物质。作为第一步，H α发射的消光校正表面亮度图与电子密度的逐点测定相结合，以确定整个星云的发射层厚度。第二步涉及计算几何形状，满足导出的发射层厚度约束、以H α为单位的表面亮度以及所有电离辐射来自单个星星θ（sup 1）Ori C的假设。这既适用于沿视线沿着恒定气体密度的情况，也适用于密度呈指数下降的更现实的情况。由此产生的模型表明，M42是一个高度不规则的物体，在电离前沿的区域，几何形状的局部斜率更陡，产生更高的表面亮度。这个模型还解释了亮条附近的局部电离变化和θ（sup 1）Ori C西南约40秒的最亮区域。
We have constructed a geometric model for the Orion Nebula exploiting the fact that most of the radiation arises from a relatively thin layer of ionized material near the ionization front on the near side of the giant molecular cloud OMC-1. As a first step, an extinction corrected surface brightness map of H alpha emission was combined with point by point determinations of the electron density to determine the thickness of the emitting layer across the nebula. The second step involved calculation of the geometry that would satisfy the derived emitting layer thickness constraint, the surface brightness in H alpha, and the assumption that all of the ionizing radiation comes from a single star, theta(sup 1) Ori C. This was done both for the case of a constant gas density along a line of sight and the more realistic case of an exponentially decreasing density. The resulting models show that M42 is a highly irregular object, with regions in the ionization front where the local slope in the geometry is steeper producing higher surface brightnesses. This model also explains local ionization variations near the Bright Bar and the brightest region about 40 sec southwest of theta(sup 1) Ori C.