Circular polarimetry and the line of sight to the Becklin-Neugebauer object
Circular polarimetry and the line of sight to the Becklin-Neugebauer object
复制标题
圆偏振测量和 Becklin-Neugebauer 物体的视线
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Chrysostomou
中科院分区：
文献类型：
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作者：
D. Aitken;J. Hough;A. Chrysostomou
水冰的3.1 μm吸收特征已经在许多分子云中被光谱学观测到，当它被光谱偏振观测到时，通常会看到相应的偏振特征。通常，在这些情况下，特别是对于Becklin-Neugebauer（BN）对象，可以看到特征和连续体之间的明显位置角偏移，这表明冰物质的分馏和沿沿着视线的变化排列方向。
在这里，依赖于圆偏振分馏沿着视线的调查，它示出了其频谱的形式，连同位置角位移的符号，表明在沿着视线的冰冷的材料在于。更具体地说，从北到东测量的冰特征中的位置角位移的符号与圆偏振冰特征的符号之间的一致性意味着冰粒被裸露的冰粒覆盖。BN的一些初步圆偏振测量具有这种特性，并且在迄今为止存在的仅有的另外两种情况下发现了类似的情况。
The 3.1-μm absorption feature of water-ice has been observed spectroscopically in many molecular clouds and, when it has been observed spectropolarimetrically, usually a corresponding polarization feature is seen. Typically, on these occasions, and particularly for the Becklin–Neugebauer (BN) object, a distinct position angle shift between the feature and continuum is seen, which indicates both a fractionation of the icy material and a changing alignment direction along the line of sight.
Here, the dependence of circular polarimetry on fractionation along the line of sight is investigated and it is shown that the form of its spectrum, together with the sign of the position angle shift, indicates where along the line of sight the icy material lies. More specifically, a coincidence between the sign of the position angle displacement in the ice feature, measured north through east, and that of the circular polarization ice feature means that the icy grains are overlaid by bare grains. Some preliminary circular polarimetry of BN has this characteristic, and a similar situation is found in the only two other cases for which relevant observations so far exist.