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arXiv 2109.12943astro-ph.HEastro-ph.SR
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你能走多低?SN 2018 zd是一颗低质量Fe核坍缩超新星

How low can you go? SN 2018zd as a low-mass Fe core-collapse supernova

E. Callis, M. Fraser, A. Pastorello, Subo Dong, S. J. Brennan, P. Chen, S. Bose, T. Reynolds, L. Salmon, P. Jonker, S. Benetti, M. Berton, G. Cannizzaro, E. Cap… 展开作者

E. Callis, M. Fraser, A. Pastorello, Subo Dong, S. J. Brennan, P. Chen, S. Bose, T. Reynolds, L. Salmon, P. Jonker, S. Benetti, M. Berton, G. Cannizzaro, E. Cappellaro, E. Congiu, S. Dyrbye, D. Eappachen, N. Elias-Rosa, M. Gromadzki, C. P. Gutiérrez, S. Holmbo, T. W. S. Holoien, K. Itagaki, E. Kankare, S. Mattila, R. Mutel, P. Ochner, R. S. Post, J. Prieto, A. Reguitti, T. Roth, J. Ryon, A. Sagués-Carracedo, B. J. Shappee, A. Siviero, K. G. Stassun, M. Stritzinger, L. Tomasella, S. Villanueva, T. Wevers, P. Wiggins

摘要:

我们介绍了SN 2018 zd的光谱学和光度学,SN 2018 zd是一颗IIP型核心坍缩超新星,在其最早的光谱中具有与环境物质相互作用的特征。高电离线是冲击波爆发的标志,但在最早的光谱期没有出现,而在爆炸后4.9d才出现在单一的光谱中。这些特征的强度和简洁性意味着在紧邻祖先的地方有一个封闭的拱星物质壳。一旦狭窄的发射线消失,SN 2018 zd的演化类似于IIP型SN,尽管SN 2018 zd的蓝色和增强的平台星等表明在整个平台阶段有额外的亮度来源。虽然SN 2018 zd以前被认为是一个电子捕获SN,但我们认为它是一个来自低质量红超巨星祖星的Fe核塌缩。对SN 2018 zd的不同解释部分是由于到宿主星系NGC 2146的距离存在很大的不确定性,我们在这里重新推导为$15.6^{+6.1}_{-3.0}$ Mpc。我们发现SN 2018 zd喷出的$^{56}$ Ni质量为0.017 M $_{\odot}$,明显高于ECSNe模型的预测。我们还发现SN 2018 zd中的Ni/Fe比远低于ECSN的预期。

英文摘要:

We present spectroscopy and photometry of SN 2018zd, a Type IIP core-collapse supernova with signatures of interaction with circumstantial material in its earliest spectra. High ionization lines, the earmark of shock breakout, are not seen in the earliest spectral epoch, and are only seen in a single spectrum at 4.9 d after explosion. The strength and brevity of these features imply a confined circumstellar material shell in the immediate vicinity of the progenitor. Once the narrow emission lines disappear, SN 2018zd evolves similarly to a Type IIP SN, although the blue colour and enhanced plateau magnitude of SN 2018zd suggests an additional source of luminosity throughout the plateau phase. While SN 2018zd has previously been proposed as an electron-capture SN, we suggest that it is an Fe core-collapse from a low mass red supergiant progenitor. Differences in interpretation for SN 2018zd arise in part due to the large uncertainty on the distance to the host-galaxy NGC 2146, which we re-derive here to be $15.6^{+6.1}_{-3.0}$ Mpc. We find the ejected $^{56}$Ni mass for SN 2018zd to be 0.017 M$_{\odot}$, significantly higher than models of ECSNe predict. We also find the Ni/Fe ratio in SN 2018zd to be much lower that would be expected for an ECSN.

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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