A quarter-century after its first observations of the full Crab Nebula, NASA’s Hubble Space Telescope has taken a fresh look at the supernova remnant. The result is an unparalleled, detailed look at the aftermath of a supernova and how it has evolved over Hubble’s long lifetime. A paper detailing the new Hubble observation is published in The Astrophysical Journal .
在首次观测完整的蟹状星云四分之一个世纪后，美国宇航局的哈勃太空望远镜重新审视了超新星遗迹。其结果是对超新星的后果以及它在哈勃漫长的一生中如何演变进行了无与伦比的详细观察。 《天体物理学杂志》上发表了一篇详细介绍哈勃新观测的论文。
This new Hubble observation continues a legacy that stretches back nearly 1,000 years, when astronomers in 1054 recorded the supernova as an impressively bright new star that, for weeks, was visible even during the day. The Crab Nebula is the aftermath of SN 1054 , located 6,500 light-years from Earth in the constellation Taurus.
哈勃望远镜的这项新观测延续了近 1000 年前的遗产，当时天文学家在 1054 年将这颗超新星记录为一颗令人印象深刻的明亮新星，在数周内即使在白天也能看到它。蟹状星云是 SN 1054 的余波，位于距地球 6,500 光年的金牛座。
“We tend to think of the sky as being unchanging, immutable,” said astronomer William Blair of Johns Hopkins University, who led the new observations. “However, with the longevity of the Hubble Space Telescope, even an object like the Crab Nebula is revealed to be in motion, still expanding from the explosion nearly a millennium ago.”
“我们倾向于认为天空是不变的，一成不变的，”领导这项新观测的约翰·霍普金斯大学天文学家威廉·布莱尔说。 “然而，随着哈勃太空望远镜的长寿，即使是像蟹状星云这样的物体也被发现处于运动状态，仍在因近千年前的爆炸而膨胀。”
The supernova remnant was discovered in the mid-18th century, and in the 1950s Edwin Hubble was among several astronomers who noted the close correlation between Chinese astronomical records of a supernova and the position of the Crab Nebula. The discovery that the heart of the Crab contained a pulsar — a rapidly rotating neutron star — that was powering the nebula’s expansion finally aligned modern observations and ancient records.
超新星遗迹是在 18 世纪中叶发现的，在 20 世纪 50 年代，埃德温·哈勃 (Edwin Hubble) 等几位天文学家注意到了中国超新星天文记录与蟹状星云位置之间的密切相关性。蟹状星云的中心含有一颗脉冲星（一颗快速旋转的中子星）的发现为星云的膨胀提供了动力，这一发现最终与现代观测和古代记录相一致。
In its new image, Hubble captured the nebula’s intricate filamentary structure, as well as the considerable outward movement of those filaments over 25 years, at a pace of 3.4 million miles per hour. Hubble is the only telescope with the combination of longevity and resolution capable of capturing these detailed changes.
在其新图像中，哈勃捕捉到了星云错综复杂的丝状结构，以及这些丝状结构在 25 年来以每小时 340 万英里的速度进行的相当大的向外运动。哈勃望远镜是唯一一款兼具寿命和分辨率的望远镜，能够捕捉这些细节变化。
For better comparison with the new image, Hubble’s 1999 image of the Crab was re-processed. The variation of colors in both of the Hubble images shows a combination of changes in local temperature and density of the gas as well as its chemical composition.
为了更好地与新图像进行比较，哈勃望远镜 1999 年拍摄的螃蟹图像进行了重新处理。两张哈勃图像中颜色的变化显示了局部温度和气体密度及其化学成分的变化。
“Even though I’ve worked with Hubble quite a bit, I was still struck by the amount of detailed structure we can see and the increased resolution with the Wide Field Camera 3 , as compared to 25 years ago ,” Blair said. Wide Field Camera 3 was installed in 2009 , the last time Hubble instruments were updated by astronauts.
布莱尔说：“尽管我已经与哈勃望远镜合作了很长时间，但与 25 年前相比，我仍然对我们可以看到的详细结构的数量以及宽视场相机 3 提高的分辨率感到震惊。”宽视场相机 3 于 2009 年安装，这是宇航员最后一次更新哈勃仪器。
Blair noted that filaments around the periphery of the nebula appear to have moved more compared to those in the center, and that rather than stretching out over time, they appear to have simply moved outward. This is due to the nature of the Crab as a pulsar wind nebula powered by synchrotron radiation, which is created by the interaction between the pulsar’s magnetic field and the nebula’s material. In other well-known supernova remnants , the expansion is instead driven by shockwaves from the initial explosion, eroding surrounding shells of gas that the dying star previously cast off.
布莱尔指出，与中心的细丝相比，星云外围的细丝似乎移动得更多，而且它们似乎只是向外移动，而不是随着时间的推移而伸展。这是由于蟹状星云的本质是由同步加速器辐射驱动的脉冲星风星云，同步加速器辐射是由脉冲星磁场与星云物质之间的相互作用产生的。在其他著名的超新星遗迹中，膨胀是由最初爆炸的冲击波驱动的，侵蚀了垂死恒星先前释放的周围气体壳。
The new, higher-resolution Hubble observations are also providing additional insights into the 3D structure of the Crab Nebula, which can be difficult to determine from a 2D image, Blair said. Shadows of some of the filaments can be seen cast onto the haze of synchrotron radiation in the nebula’s interior. Counterintuitively, some of the brighter filaments in the latest Hubble images show no shadows, indicating they must be located on the far side of the nebula.
布莱尔说，新的、更高分辨率的哈勃观测还为蟹状星云的 3D 结构提供了更多的见解，这很难从 2D 图像中确定。可以看到一些细丝的阴影投射在星云内部同步加速器辐射的薄雾上。与直觉相反，最新的哈勃图像中一些较亮的细丝没有显示任何阴影，表明它们一定位于星云的远端。
According to Blair, the real value of Hubble’s Crab Nebula observations is still to come. The Hubble data can be paired with recent data from other telescopes that are observing the Crab in different wavelengths of light. NASA’s James Webb Space Telescope released its infrared-light observations of the Crab Nebula in 2024. Comparison of the Hubble image with other contemporary multiwavelength observations will help scientists put together a more complete picture of the supernova’s continuing aftermath, centuries after astronomers first wondered at a new little star twinkling in the sky.
布莱尔表示，哈勃蟹状星云观测的真正价值尚未显现。哈勃数据可以与其他望远镜在不同波长的光下观察螃蟹的最新数据配对。美国宇航局詹姆斯·韦伯太空望远镜于 2024 年发布了对蟹状星云的红外光观测结果。将哈勃图像与其他当代多波长观测结果进行比较，将有助于科学家们对超新星持续的后果形成更完整的了解，而距离天文学家首次发现一颗新的小恒星在天空中闪烁已经过去了几个世纪。
The Hubble Space Telescope has been operating for more than three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at NASA Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
哈勃太空望远镜已经运行了三十多年，并不断做出突破性的发现，塑造我们对宇宙的基本理解。哈勃望远镜是 NASA 和 ESA（欧洲航天局）之间的国际合作项目。美国宇航局位于马里兰州格林贝尔特的戈达德太空飞行中心负责管理望远镜和任务操作。总部位于丹佛的洛克希德·马丁航天公司还支持美国宇航局戈达德的任务运营。位于巴尔的摩的太空望远镜科学研究所由天文学研究大学协会运营，为美国宇航局进行哈勃科学操作。