科学发布：天文学家捕捉到大质量星死亡的最初爆发时刻

天文学家捕捉到大质量星死亡的最初爆发时刻

Astronomers Catch Massive Star’s Death From the First Explosive Moment

凭借极其微弱的X射线爆发且没有高速喷射，这颗超新星（supernova）揭示了大质量星（massive star）终结生命的一种新方式。

With an extremely faint burst of X-rays and no high-velocity jets, this supernova suggests a new way for massive stars to end their lives

2026年8月5日

5 August 2026

一场罕见的宇宙爆炸让天文学家（astronomer）得以以前所未有的视角观察一颗大质量星的最后时刻，揭示了普通超新星与宇宙中最具能量的爆炸之间此前缺失的联系。美国国家科学基金会（National Science Foundation, NSF）下属的美国国家光学红外天文研究实验室（NOIRLab）的多项设施和仪器助力揭开了这一事件的本质，包括美国能源部制造的暗能量相机（Dark Energy Camera）、美国国家科学基金会尼古拉斯·U·梅亚尔4米望远镜（Nicholas U. Mayall 4-meter telescope）以及NSF与美国能源部（DOE）共同建设的薇拉·鲁宾天文台（Vera C. Rubin Observatory）。

A rare cosmic explosion has given astronomers an unprecedented view of a massive star in its final moments, revealing a previously missing link between ordinary supernovae and the most energetic explosions in the Universe. Several NSF NOIRLab facilities and instruments helped to unravel the nature of this event, including the U.S. Department of Energy-fabricated Dark Energy Camera, the U.S. National Science Foundation Nicholas U. Mayall 4-meter telescope, and NSF–DOE Vera C. Rubin Observatory.

2026年3月，爱因斯坦探针（Einstein Probe）探测到来自约5亿光年（light year）外一个星系的短暂软X射线闪光。这次闪光被命名为EP260321a，随即引发了全球范围的观测活动。在一小时内，地基望远镜（ground-based telescope）开始监测该源，揭示了一颗迅速增亮的超新星，随后被命名为SN 2026gzf。两支科学家团队利用多项NSF NOIRLab设施对该事件进行了观测，并监测其光度（luminosity）演变过程。

In March 2026, the Einstein Probe detected a brief flash of soft X-rays emitted from a galaxy about 500 million light-years away. The flash, dubbed EP260321a, immediately triggered a worldwide observing campaign. Within an hour, ground-based telescopes began monitoring the source, revealing a rapidly brightening supernova later designated SN 2026gzf. Two teams of scientists utilized several NSF NOIRLab facilities to observe the event and monitor its evolving light profile.

这些团队由卡内基梅隆大学的天文学家兼麦克威廉姆斯研究员Brendan O’Connor，以及马里兰大学帕克分校的美国[国家]航天局（NASA）爱因斯坦研究员Jillian Rastinejad领导。团队在《天体物理学报通信》（Astrophysical Journal Letters）上发表了他们的研究结果（O’Connor等，Rastinejad等）。

The teams were led by Brendan O’Connor, astronomer and McWilliams Fellow at Carnegie Mellon University, and Jillian Rastinejad, a NASA Einstein Fellow at the University of Maryland, College Park. The teams present the results of their studies in papers published in The Astrophysical Journal Letters (O’Connor et al., Rastinejad et al.).

两支团队均独立确认了最初的X射线爆发为“激波溃围（shock breakout）”——即来自恒星爆炸的强大激波（shock wave）冲破恒星表面并释放出超新星第一缕光的时刻。

Both teams were able to independently identify the initial burst of X-rays as a “shock breakout” — the moment when the powerful shock wave from a stellar explosion bursts through the star’s surface and releases the first light of a supernova.

尽管预计所有超新星爆发都会发生激波溃围，但由于其持续时间仅为几秒到几小时，观测难度极大。在过去二十年中，天文学家仅确认了另一起清晰的X射线激波溃围事件[1]，这使得EP260321a成为一项极其罕见的发现。

Although shock breakouts are expected to occur in all supernova explosions, they are notoriously difficult to observe because they last only seconds to hours. In the past two decades, astronomers have confidently identified only one other clear X-ray shock breakout event [1], making EP260321a an exceptionally rare discovery.

每支团队也都独立证实了该爆炸为宽线Ic型（Ic-BL）超新星。此类超新星通常拥有相对论性喷射（relativistic jet）——即以接近光速（speed of light）运动的物质——并且通常与伽马射线暴有关，后者是宇宙中最明亮、最强大的爆炸类别。

Each team was also able to independently confirm that the explosion was a broad-lined Type Ic (Ic-BL) supernova. These supernovae typically possess jets of relativistic material — material that is moving close to the speed of light — and they are commonly linked to gamma-ray bursts, which are the brightest and most powerful class of explosions in the Universe.

然而，SN 2026gzf因多种原因成为一个独特的案例。首先，尽管爆炸本身并不微弱，但其初始激波溃围是迄今为止与Ic-BL超新星相关的最微弱的一次。此外，研究人员惊讶地发现，尽管该事件看起来与其他随后发生伽马射线暴的Ic-BL超新星相符，但并未发现超新星后伴随伽马射线暴的证据。

However, SN 2026gzf stands out as a unique case for multiple reasons. First, the initial shock breakout is the faintest to ever be associated with a Ic-BL supernova, even though the explosion itself was not similarly weak. Additionally, researchers were surprised to find no evidence of a gamma-ray burst following the supernova, despite the event appearing to match other Ic-BL supernovae that were followed by gamma-ray bursts.

“SN 2026gzf看起来与此前已知的、与伽马射线暴相关联的高能超新星非常相似。然而，利用最灵敏的设施进行的多波段（multi-band）随动（follow-up）观测却未发现相对论性喷射或余辉的证据，而这些通常在同类事件中可见，”O’Connor说。“一种可能性是喷射被‘扼杀’了，要么是被恒星表面，要么是被恒星周围的星周物质（circumstellar material）所阻挡。”

“SN 2026gzf looks remarkably similar to other energetic supernovae that have been previously linked to gamma-ray bursts. Yet multi-wavelength follow-up observations using the most sensitive facilities found no evidence for a relativistic jet or an afterglow, which are typically seen in those events,” says O’Connor. “One possibility is that the jet was ‘choked,’ either by the surface of the star or by circumstellar material surrounding the star.”

为了调查这一令人困惑的事件，O’Connor及其团队利用安装在智利托洛洛山美洲天文台（CTIO）——NSF NOIRLab的一个项目——的NSF维克多·M·布兰科4米望远镜（Víctor M. Blanco 4-meter Telescope）上的5.7亿像素DOE制造的暗能量相机（DECam），在超新星增亮并达到峰值光度时获取了深空成像。爆炸前十年拍摄的DECam存档图像显示，在同一位置存在一个蓝色源[2]，为前身星（progenitor star）及其在恒星死亡前的环境提供了罕见的线索。

For their investigation into this puzzling event, O’Connor and his team acquired deep imaging of the supernova as it brightened and reached peak luminosity using the 570-megapixel DOE-fabricated Dark Energy Camera (DECam), mounted on the NSF Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile, a Program of NSF NOIRLab. Archival DECam images taken ten years before the explosion revealed a blue source at the same location [2], offering rare clues about the progenitor system and its environment before the star died.

该事件也发生在NSF–DOE薇拉·鲁宾天文台的宇宙演化巡天（COSMOS）深钻场内。来自鲁宾天文台警报代理程序Babamul的公开调试数据提供了额外的多波段观测资料，有助于追踪超新星的演化，并揭示了前身星在爆炸前不久的活动迹象。得益于鲁宾天文台的快速节奏和前所未有的灵敏度，预计持续的观测将为该超新星在未来几年的演化提供详细的长期记录。

The event also occurred within the NSF–DOE Vera C. Rubin Observatory’s COSMOS Deep Drilling Field. Public commissioning data from the Rubin alert broker, Babamul, supplied additional multi-band observations that helped track the supernova’s evolution and revealed evidence of activity from the progenitor system shortly before the explosion. Thanks to Rubin’s rapid cadence and unprecedented sensitivity, continued observations are expected to provide detailed, long-term records of the supernova as it evolves for years to come.

此外，安装在NSF NOIRLab项目之一的基特峰国家天文台（KPNO）的NSF尼古拉斯·U·梅亚尔4米望远镜上的暗能量光谱仪（DESI），通过其备用光纤瞬变项目获得了多条光谱。该项目旨在利用DESI上未匹配目标的备用光纤，对鲁宾天文台识别出的瞬变源进行随动观测。这些观测使团队能够观察SN 2026gzf随时间的演变，并确认其作为Ic-BL超新星的本质。

Additionally, the Dark Energy Spectroscopic Instrument (DESI), mounted on the NSF Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab, obtained multiple spectra through its spare-fiber transient program. This program is aimed at using spare fibers on DESI that are not already matched to a target to follow up on transients identified by Rubin. These observations allowed the team to watch SN 2026gzf evolve over time and confirm its nature as a Ic-BL supernova.

“DESI的备用光纤项目让我们有机会反复回到SN 2026gzf，并跟踪其光谱随爆炸演化而发生的变化，”卡内基梅隆大学研究生、O’Connor团队成员及论文第二作者Xander Hall说。“这一系列观测展示了利用DESI备用光纤进行快速瞬变随动和分类的强大能力，随着鲁宾天文台在未来十年不断增加其瞬变警报流，这种能力将愈发重要。”

“DESI’s spare-fiber program gave us the opportunity to return to SN 2026gzf repeatedly and follow how its spectrum changed as the explosion evolved,” says Xander Hall, graduate student at Carnegie Mellon University, member of O’Connor’s team, and second author of the paper. “This sequence of observations demonstrates the power of using DESI’s spare fibers for rapid transient follow-up and classification as Rubin continues to ramp up its transient alert stream over the next decade.”

在研究中，O'Connor及其团队还获取了来自NASA钱德拉X射线天文台（Chandra X-ray Observatory）、美国国家射电天文台（National Radio Astronomy Observatory）的甚大阵（Very Large Array）、路德维希-马克西米利安大学温德尔斯坦天文台的弗劳恩霍夫望远镜、加州理工学院帕洛玛天文台（Palomar Observatory）望远镜、霍比-埃伯利望远镜（Hobby-Eberly Telescope）以及南非大型望远镜（SALT）的观测数据。

For their study, O'Connor and his team also acquired observations from NASA's Chandra X-ray Observatory, the National Radio Astronomy Observatory’s Very Large Array (VLA), the Fraunhofer Telescope at Wendelstein Observatory of Ludwig-Maximilians-Universität, Caltech's Palomar Observatory telescopes, the Hobby-Eberly Telescope, and the Southern African Large Telescope (SALT).

Rastinejad及其团队利用位于夏威夷的北双子望远镜（Gemini North）和智利的南双子望远镜（Gemini South）上安装的双子多天体摄谱仪（GMOS）——两者共同组成了国际双子天文台（International Gemini Observatory）——以及通过AEON队列安装在SOAR 4.1米望远镜上的Goodman摄谱仪，对该事件进行了多波段随动调查；双子望远镜和SOAR均由美国国家科学基金会（NSF）部分资助，并由美国国家光学红外天文研究实验室（NOIRLab）运营。他们还使用了来自NSF-DOE薇拉·鲁宾天文台（Rubin Observatory）、帕洛玛天文台（Palomar Observatory）和甚大阵（VLA）的数据。

Rastinejad and her team simultaneously conducted a multi-wavelength follow-up investigation of the event using both of the Gemini Multi-Object Spectrographs (GMOS) mounted on Gemini North in Hawai‘i and Gemini South in Chile, which compose the International Gemini Observatory, and the Goodman spectrograph mounted on the SOAR 4.1-meter Telescope through its AEON queue; both Gemini and SOAR are supported in part by the NSF and operated by NSF NOIRLab. They also used data from NSF–DOE Rubin Observatory, Palomar Observatory, and the VLA.

这些观测帮助Rastinejad及其团队确认了SN 2026gzf是一颗Ic-BL型超新星，确定了其不存在相对论性喷射，并了解了该恒星在坍缩前的结构及其周围环境。

These observations helped Rastinejad and her team confirm that SN 2026gzf was a Ic-BL supernova, determine the absence of relativistic jets, and understand the star’s structure and surroundings just prior to collapse.

“我们的观测使我们能够研究这次爆发中三个部分的物理特性：X射线激波溃围、伴随的超新星，以及超新星与垂死恒星先前抛出物质的相互作用，”Rastinejad说。“通过这些信息，我们能够绘制出恒星周围物质的结构，并了解该恒星在坍缩前剧烈的生活方式。”

“Our observations allowed us to study the physics of three pieces of this explosion: the X-ray shock breakout, the accompanying supernova, and the interaction of the supernova with material previously cast out by the dying star,” says Rastinejad. “With this information we were able to map out the structure of the material surrounding the star and understand the star’s violent lifestyle before it collapsed.”

他们确定该前身星是一颗沃尔夫-拉叶星（Wolf-Rayet star）——一颗出生时质量约为太阳20倍，并在生命早期就耗尽了氢的恒星。他们发现，在走向爆炸性死亡的过程中，该恒星经历了不规则的质量损失阶段，抛射了其所有的氢和氦，留下了一颗主要由碳和氧组成的剥离恒星。这种湍流式的质量损失在恒星周围形成了多层物质壳：一个发射出初始X射线信号的近距离、致密的低质量物质壳，以及一个发射出光学超新星信号的扩展、非对称物质壳。

They determined that the progenitor is a Wolf-Rayet star — a star born with about 20 times the mass of the Sun that burns through its hydrogen early on in its life. They found that in the lead-up to its explosive death, the star underwent irregular episodes of mass loss, ejecting all of its hydrogen and helium and leaving behind a stripped star made mostly of carbon and oxygen. The turbulent mass loss created multiple shells of material around the star: a nearby, compact shell of low-mass material that emitted the initial X-ray signal, plus an extended, non-symmetric shell of material that emitted the optical supernova signal.

“这是我们首次绘制出氢氦被剥离恒星的爆炸前环境，”马里兰大学应届博士毕业生、Rastinejad团队成员及论文第二作者Gokul Srinivasaragavan说。“展望未来，我很兴奋能以同样的细节观测更多的激波溃围事件，以测试所有被剥离的恒星在坍缩前是否都有相似的‘生活方式’，以及我们能观察到哪些差异（如果有的话）。”

“This is the first time we’ve mapped out the pre-explosion environment of a star that has been stripped of hydrogen and helium,” says Gokul Srinivasaragavan, a recent PhD graduate from the University of Maryland, a member of Rastinejad’s team, and second author on the paper. “Going forward, I’m excited to observe more shock breakout events in similar detail to test if all stripped stars have a similar ‘lifestyle’ prior to collapse and what, if any, differences we see.”

由于具有极其微弱的X射线激波溃围且没有相对论性外流，EP260321a/SN 2026gzf成为了普通超新星激波溃围与产生低光度伽马射线暴的极端爆炸之间的一座独特桥梁。

With an exceptionally faint X-ray shock breakout and no relativistic outflows, EP260321a/SN 2026gzf acts as a unique bridge between ordinary supernova shock breakouts and the more extreme explosions that generate low-luminosity gamma-ray bursts.

通过确立高能Ic-BL型超新星并不总是产生伽马射线暴、相对论性外流或长寿命余辉，这一发现表明大质量星死亡的路径比以往认知的更为广泛。

By establishing that energetic Ic-BL supernovae do not always produce a gamma-ray burst, relativistic outflows, or a long-lived afterglow, this discovery suggests that massive stars can die through a wider range of pathways than previously recognized.

该结果还展示了协同式时域天文学日益增长的力量，即航天任务与地基天文台共同合作，实时捕捉瞬态宇宙事件。通过结合来自爱因斯坦探针（Einstein Probe）、NOIRLab设施以及世界各地合作天文台的观测数据，研究人员得以以前所未有的细节重建了一次罕见的爆炸。

The result also demonstrates the growing power of coordinated time-domain astronomy, where space missions and ground-based observatories work together to capture transient cosmic events in real time. By combining observations from Einstein Probe, NSF NOIRLab facilities, and partner observatories around the world, researchers were able to reconstruct a rare explosion in unprecedented detail.

注

Notes

[1] 超新星SN 2008D于2008年被美国国家航天局（NASA）的格雷尔斯雨燕天文台（Neil Gehrels Swift Observatory）探测到。这是天文学家首次直接探测到核区坍缩超新星的初始激波溃围。

[1] Supernova SN 2008D was detected by NASA’s Neil Gehrels Swift Observatory in 2008. It was the first time astronomers directly detected the initial shock breakout of a core-collapse supernova.

[2] 科学家表示，超新星位置在爆炸前图像中的明亮辐射，很可能代表了宿主星系中一个致密、极端的恒星形成区，并结合了前身星在死亡前的爆炸前活动。

[2] Scientists say that the bright emission at the location of the supernova in pre-explosion images likely represents a compact, extreme star-forming region in the host galaxy, combined with pre-explosion activity of the progenitor star before its death.