一颗大质量恒星在死亡前猛烈抛射出星周物质  

Circumstellar material ejected violently by a massive star immediately before its death

作　　者：张居甲 林含 王晓锋 赵泽毅 李丽萍 刘嘉联 闫圣钰 向丹凤 王汇娟 白金明 Jujia Zhang;Han Lin;Xiaofeng Wang;Zeyi Zhao;Liping Li;Jialian Liu;Shengyu Yan;Danfeng Xiang;Huijuan Wang;Jinming Bai(Yunnan Observatories(YNAO),Chinese Academy of Sciences,Kunming 650216,China;Key Laboratory for the Structure and Evolution of Celestial Objects,Chinese Academy of Sciences,Kunming 650216,China;International Centre of Supernovae,Yunnan Key Laboratory,Kunming 650216,China;Key Laboratory of Radio Astronomy and Technology,CAS,Beijing 100101,China;Department of Physics,Tsinghua University,Beijing 100084,China;Beijing Planetarium,Beijing Academy of Science and Technology,Beijing 100044,China;National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]Yunnan Observatories(YNAO),Chinese Academy of Sciences,Kunming 650216,China [2]Key Laboratory for the Structure and Evolution of Celestial Objects,Chinese Academy of Sciences,Kunming 650216,China [3]International Centre of Supernovae,Yunnan Key Laboratory,Kunming 650216,China [4]Key Laboratory of Radio Astronomy and Technology,CAS,Beijing 100101,China [5]Department of Physics,Tsinghua University,Beijing 100084,China [6]Beijing Planetarium,Beijing Academy of Science and Technology,Beijing 100044,China [7]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [8]School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 101408,China

出　　处：《Science Bulletin》2023年第21期2548-2554,M0005,共8页科学通报（英文版）

基　　金：supported by the National Key R&D Program of China(2021YFA1600404);the National Natural Science Foundation of China(12173082);science research grants from the China Manned Space Project(CMS-CSST-2021-A12);the Yunnan Province Foundation(202201AT070069);the Top-notch Young Talents Program of Yunnan Province;the Light of West China Program provided by the Chinese Academy of Sciences;the International Centre of Supernovae,Yunnan Key Laboratory(202302AN360001);supported by the National Natural Science Foundation of China(12288102,12033003,and 11633002);the Scholar Program of Beijing Academy of Science and Technology(DZ:BS202002)。

摘　　要：Ⅱ型超新星是宇宙中最常见的恒星爆炸,其富氢的大质量前身星最后阶段的演变让人捉摸不透.这类恒星晚期演化和由此产生的星周环境的差异导致了超新星丰富的观测多样性.为了建立Ⅱ型超新星爆炸与大质量恒星晚期演化之间的联系,有必要捕捉超新星爆炸的第一缕光,即由激波爆发冷却产生的高能光子电离星周物质造成的闪亮光谱.近邻星系M 101中爆发的SN 2023ixf为探索这个问题提供了难得的机会.本文利用爆炸后1~5天内频繁拍摄地闪亮光谱,对这颗超新星周围物质的性质进行严格的约束.计算得出,SN 2023ixf前身星在爆炸前最后2~3年中以高达M≈6×10^(-4)M⊙a^(-1)速率损失物质.这些物质以55 km s^(-1)的速度运动,在距离前身星不到7×10^(14)cm的位置形成致密的星周物质壳层.考虑到如此高的质量损失率和相对较大的风速,以及20年前的前身星图像,SN2023ixf可能是刚从红超巨星演化而来的黄巨超巨星产生的超新星爆炸.Type II supernovae represent the most common stellar explosions in the Universe,for which the final stage evolution of their hydrogen-rich massive progenitors towards core-collapse explosion are elusive.The recent explosion of SN 2023ixf in a very nearby galaxy,Messier 101,provides a rare opportunity to explore this longstanding issue.With the timely high-cadence flash spectra taken within 1–5 days after the explosion,we can put stringent constraints on the properties of the surrounding circumstellar material around this supernova.Based on the rapid fading of the narrow emission lines and luminosity/profile of Ha emission at very early times,we estimate that the progenitor of SN 2023ixf lost material at a massloss rate M≈6×10^(-4)M⊙a^(-1)over the last 2–3 years before explosion.This close-by material,moving at a velocity vw55 km s^(-1),accumulates a compact CSM shell at the radius smaller than 71014 cm from the progenitor.Given the high mass-loss rate and relatively large wind velocity presented here,together with the pre-explosion observations made about two decades ago,the progenitor of SN 2023ixf could be a short-lived yellow hypergiant that evolved from a red supergiant shortly before the explosion.

关 键 词：超新星爆炸 星周物质 前身星 Ⅱ型超新星 红超巨星 近邻星系 质量损失率 

分 类 号：P152[天文地球—天文学]