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arXiv 0904.0119astro-ph.SR
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I In型超新星SN 2007 rt的非对称性证据

Evidence of Asymmetry in SN 2007rt, a Type IIn Supernova

C. Trundle, A. Pastorello, S. Benetti, R. Kotak, S. Valenti, I. Agnoletto, F. Bufano, M. Dolci, N. Elias-Rosa, T. Greiner, D. Hunter, F. P. Keenan, V. Lorenzi, … 展开作者

C. Trundle, A. Pastorello, S. Benetti, R. Kotak, S. Valenti, I. Agnoletto, F. Bufano, M. Dolci, N. Elias-Rosa, T. Greiner, D. Hunter, F. P. Keenan, V. Lorenzi, K. Maguire, S. Taubenberger

摘要:

本文介绍了对缓慢演化的I型In SN 2007 rt的光学光度和光谱分析,涵盖了发现后481天的时间。它最早的光谱是在爆发时期后约100天拍摄的,表明存在一种致密的星周介质,超新星喷出物与之相互作用。这是由缓慢演变的光变曲线支持的。SN 2007 rt的光谱中有一个显著的特徴,就是有一条很宽的He I 5875谱线,这在IIn型超新星中是不常见的。这可能意味着这颗恒星的祖先有很高的He/H比,通过质量损失已经脱落了相当大一部分的氢壳。一个中等分辨率的光谱揭示了一个狭窄的H α P-Cygni轮廓,其吸收分量的宽度为128公里/秒。这种缓慢的速度表明SN 2007 rt的前身最近经历了质量损失,风速与亮蓝色变量检测到的下限相当。在早期阶段的H和He的线轮廓的不对称性具有一些相似的双峰特征中观察到的一些Ib/c谱。这些不对称性可能表明不对称或双极流出,或者在快速膨胀的喷出物中形成尘埃。此外,爆炸后240多天的后期光谱显示了新形成的尘埃存在的明确证据。

英文摘要:

An optical photometric and spectroscopic analysis of the slowly-evolving Type IIn SN2007rt is presented, covering a duration of 481 days after discovery. Its earliest spectrum, taken approximately 100 days after the explosion epoch, indicates the presence of a dense circumstellar medium, with which the supernova ejecta is interacting. This is supported by the slowly-evolving light curve. A notable feature in the spectrum of SN 2007rt is the presence of a broad He I 5875 line, not usually detected in Type IIn supernovae. This may imply that the progenitor star has a high He/H ratio, having shed a significant portion of its hydrogen shell via mass-loss. An intermediate resolution spectrum reveals a narrow Halpha P-Cygni profile, the absorption component of which has a width of 128 km/s. This slow velocity suggests that the progenitor of SN 2007rt recently underwent mass-loss with wind speeds comparable to the lower limits of those detected in luminous blue variables. Asymmetries in the line profiles of H and He at early phases bears some resemblance to double-peaked features observed in a number of Ib/c spectra. These asymmetries may be indicative of an asymmetric or bipolar outflow or alternatively dust formation in the fast expanding ejecta. In addition, the late time spectrum, at over 240 days post-explosion, shows clear evidence for the presence of newly formed dust.

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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