arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1105.4795astro-ph.GA
收藏

红矩形发光带的偏振

On the polarisation of the Red Rectangle optical emission bands

N. L. J. Cox, B. H. Foing, J. Cami, P. J. Sarre

摘要:

朝向红色矩形看到的窄光发射带的起源还不清楚。在本文中,我们进一步调查的建议,这些是由于发光的大碳分子。从某些不对称分子旋转体中可以预期到百分之几的偏振信号。安装在CFHT上的ESPaDOnS阶梯光栅摄谱仪被用来获得红矩形星云发射的高分辨率光谱偏振数据。5800、5850和6615埃的RRB在距离中央恒星东北7”和13”的星云发射光谱中被检测到。5826和6635埃的RRB只在最靠近中央恒星的位置被探测到。对于这两个位置的斯托克斯Q和U光谱显示没有明确的偏振信号中的任何RRB。我们得出的上限为0.02%的线偏振这些RRB。对于5800 RRB,在7”偏移处观察到峰值偏振为0.05%的试验性特征。然而,光谱表明,这可能是一个仪器的人工制品。检测到的五个RRB缺乏清晰的偏振信号意味着,如果发射是由于复杂有机物的发光引起的,则这些气相分子载体可能具有高度对称性,因为它们不表现出Q分支在其旋转轮廓中,尽管这可能会被统计效应修改。

英文摘要:

The origin of the narrow optical emission bands seen toward the Red Rectangle is not yet understood. In this paper we investigate further the proposal that these are due to luminescence of large carbonaceous molecules. Polarised signals of several percent could be expected from certain asymmetric molecular rotators. The ESPaDOnS echelle spectrograph mounted at the CFHT was used to obtain high-resolution optical spectropolarimetric data of the Red Rectangle nebular emission. The RRBs at 5800, 5850, and 6615 Angstrom are detected in spectra of the nebular emission 7" and 13" North-East from the central star. The 5826 and 6635 Angstrom RRB are detected only at the position nearest to the central star. For both positions the Stokes Q and U spectra show no unambiguous polarisation signal in any of the RRBs. We derive an upper limit of 0.02% line polarisation for these RRBs. A tentative feature with peak polarisation of 0.05% is seen for the 5800 RRB at 7" offset. However, the Null spectra suggest that this may be an instrumental artifact. The lack of a clear polarisation signal for the five detected RRBs implies that, if the emission is due to luminescence of complex organics, these gas-phase molecular carriers are likely to have a high degree of symmetry, as they do not exhibit a Q-branch in their rotational profile, although this may be modified by statistical effects.

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。

↑