The electron-capture origin of supernova 2018zd-猫眼课题宝

DOI：

10.1038/s41550-021-01384-2

发表时间：

2020-11

期刊：

Nature Astronomy

影响因子：

14.1

通讯作者：

中科院分区：

物理与天体物理1区

文献类型：

作者：

D. Hiramatsu;D. Howell;S. V. van Dyk;Jared A. Goldberg;K. Maeda;T. Moriya;N. Tominaga;K. Nomoto;G. Hosseinzadeh;I. Arcavi;C. McCully;J. Burke;K. Bostroem;S. Valenti;Yize Dong;P. Brown;J. Andrews;C. Bilinski;G. Williams;Paul S. Smith;N. Smith;D. Sand;G. Anand;Chengyuan Xu;A. Filippenko;M. Bersten;G. Folatelli;P. Kelly;T. Noguchi;K. Itagaki

在白矮星形成和铁核坍缩超新星之间的过渡质量范围（~ 8-10太阳质量），恒星有望产生电子俘获超新星。理论上，这些祖恒星被认为是具有简并的O + Ne + Mg核的超渐近巨型分支恒星，电子捕获到Ne和Mg核上应该会引发核坍缩，，-。然而，由于理论预测的不确定性，没有一颗超新星被明确地从电子捕获起源中识别出来。在这里，我们提出了六个电子捕获超新星的指标，并表明超新星2018zd是已知的唯一一个有强有力证据证明或与所有六个指标一致的超新星：祖祖识别，星周物质，化学成分，-，爆炸能量，光曲线和核合成，，，-。对于超新星2018zd，我们根据爆炸前图像中的微弱候选者和早期紫外线颜色和闪光光谱显示的化学富集的星周物质推断出一个超渐近的巨型分支祖先。光曲线形态和星云发射线可以用低爆炸能量和电子俘获超新星产生的富中子核合成来解释。这一鉴定为复杂的恒星演化、超新星物理、宇宙核合成和过渡质量范围内的残余种群提供了见解。

In the transitional mass range (~8–10 solar masses) between white dwarf formation and iron core-collapse supernovae, stars are expected to produce an electron-capture supernova. Theoretically, these progenitors are thought to be super-asymptotic giant branch stars with a degenerate O + Ne + Mg core, and electron capture onto Ne and Mg nuclei should initiate core collapse, , –. However, no supernovae have unequivocally been identified from an electron-capture origin, partly because of uncertainty in theoretical predictions. Here we present six indicators of electron-capture supernovae and show that supernova 2018zd is the only known supernova with strong evidence for or consistent with all six: progenitor identification, circumstellar material, chemical composition, –, explosion energy, light curve and nucleosynthesis, , , –. For supernova 2018zd, we infer a super-asymptotic giant branch progenitor based on the faint candidate in the pre-explosion images and the chemically enriched circumstellar material revealed by the early ultraviolet colours and flash spectroscopy. The light-curve morphology and nebular emission lines can be explained by the low explosion energy and neutron-rich nucleosynthesis produced in an electron-capture supernova. This identification provides insights into the complex stellar evolution, supernova physics, cosmic nucleosynthesis and remnant populations in the transitional mass range.

The electron-capture origin of supernova 2018zd

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