近日，以色列魏茨曼科学研究所的E. A. Zimmerman及其研究小组取得一项新进展。经过不懈努力，他们揭示超新星2023ixf复杂的星周环境。相关研究成果已于2024年3月27日在国际权威学术期刊《自然》上发表。

该研究团队报道了邻近的Messier101 (M101)星系中SN2023ixf的紫外光谱。利用紫外数据以及一套全面的多波长观测，研究人员暂时解决了由超新星辐射加热的厚介质产生爆炸激波的问题。他们绘制出一个精确的热光度曲线，揭示了激波是从一个远大于典型超巨星的致密层中爆发出来的。

据悉，超新星(SN)的早期演化可以揭示环境和前身星的信息。当一颗恒星在真空中爆炸时，最初从星体表面逃逸出的光子会以短暂的激波爆发形式出现，持续数小时，随后进入冷却辐射阶段。然而，对于那些在密集且光学厚的星周物质（CSM）中爆炸的恒星，第一批光子需要穿越恒星边缘以外的物质才能逃逸，这使得初始耀斑的持续时间延长至数天。在此期间，逃逸出的辐射显示出光球加热的迹象。由于早期偶然观测中缺乏紫外线（UV）数据，因此无法确定早期辐射是加热还是冷却，从而难以准确判断早期爆炸事件的性质。

附：英文原文

Title: The complex circumstellar environment of supernova 2023ixf

Author: Zimmerman, E. A., Irani, I., Chen, P., Gal-Yam, A., Schulze, S., Perley, D. A., Sollerman, J., Filippenko, A. V., Shenar, T., Yaron, O., Shahaf, S., Bruch, R. J., Ofek, E. O., De Cia, A., Brink, T. G., Yang, Y., Vasylyev, S. S., Ben Ami, S., Aubert, M., Badash, A., Bloom, J. S., Brown, P. J., De, K., Dimitriadis, G., Fransson, C., Fremling, C., Hinds, K., Horesh, A., Johansson, J. P., Kasliwal, M. M., Kulkarni, S. R., Kushnir, D., Martin, C., Matuzewski, M., McGurk, R. C., Miller, A. A., Morag, J., Neil, J. D., Nugent, P. E., Post, R. S., Prusinski, N. Z., Qin, Y., Raichoor, A., Riddle, R., Rowe, M., Rusholme, B., Sfaradi, I., Sjoberg, K. M., Soumagnac, M., Stein, R. D., Strotjohann, N. L., Terwel, J. H., Wasserman, T., Wise, J., Wold, A., Yan, L., Zhang, K.

Issue&Volume: 2024-03-27

Abstract: The early evolution of a supernova (SN) can reveal information about the environment and the progenitor star. When a star explodes in vacuum, the first photons to escape from its surface appear as a brief, hours-long shock-breakout flare, followed by a cooling phase of emission. However, for stars exploding within a distribution of dense, optically thick circumstellar material (CSM), the first photons escape from the material beyond the stellar edge and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating. Early serendipitous observations2,4 that lacked ultraviolet (UV) data were unable to determine whether the early emission is heating or cooling and hence the nature of the early explosion event. Here we report UV spectra of the nearby SN2023ixf in the galaxy Messier101 (M101). Using the UV data as well as a comprehensive set of further multiwavelength observations, we temporally resolve the emergence of the explosion shock from a thick medium heated by the SN emission. We derive a reliable bolometric light curve that indicates that the shock breaks out from a dense layer with a radius substantially larger than typical supergiants.

DOI: 10.1038/s41586-024-07116-6

Source: https://www.nature.com/articles/s41586-024-07116-6