狮子星云在韦布望远镜下焕发活力

在观测星光熠熠的太空“平原”时，美国国家航天局（NASA）/欧洲航天局（ESA）/加拿大航天局（CSA）的韦布空间望远镜（James Webb Space Telescope）拍摄了NGC 2392的图像，该天体被戏称为狮子星云（Lion Nebula）。

Observing across the starry 'plains' of space, the NASA/ESA/CSA James Webb Space Telescope has taken images of NGC 2392, nicknamed the Lion Nebula.

美国国家航天局（NASA）/欧洲航天局（ESA）的哈勃空间望远镜（Hubble Space Telescope）曾于2000年观测过这个行星状星云（planetary nebula），在可见光（visible light）下成像了这一狮子脸形状的目标，并揭示了诸如朦胧的彗星（comet）状物体组成的“鬃毛”等特征。现在，凭借其高分辨率（high resolution）成像能力，韦布望远镜捕捉到了狮子星云更清晰、更详细的视图。

The NASA/ESA Hubble Space Telescope previously viewed this planetary nebula in 2000, imaging the lion face-shaped target in visible light and revealing features such as the “mane” of hazy, comet-shaped objects. Now Webb has captured a clearer, more detailed view of the Lion Nebula due to its high-resolution imaging.

乍一看，韦布望远镜的红外图像（通过近红外照相机NIRCam和中红外仪器MIRI拍摄）所呈现的星云整体结构，可能与哈勃望远镜早期的可见光视图非常相似。然而，韦布的红外视觉突显了诸如致密尘埃团和电离气体雾霭等特征。这些气体和尘埃集合体经历了数千年才达到目前的形状，且星云的组成部分仍在不断变化。

At first glance the nebula’s overall structure in Webb’s infrared images, both with the NIRCam (Near Infrared Camera) and MIRI (Mid-Infrared Instrument), may look quite similar to Hubble's earlier visible-light view. However, Webb's infrared vision highlights features like compact clumps of dust and haze of ionised gas. It’s taken several thousand years for this collection of gas and dust to reach its current shape, and the nebula’s components continue to be altered.

这些持续变化的源头以及狮子星云独特外观的原因位于中心：一颗垂死恒星（star）的残骸。虽然它看起来像狮子的纽扣鼻，但中心白矮星（white dwarf）的能量正在驱动此处所见的复杂结构。

The source of these constant changes and the reason for the Lion Nebula’s distinct appearance is located at the centre: the remains of a dying star. Though it looks like the button nose of the lion, the central white dwarf's energy is powering the intricate structures seen here.

构成狮子脸部的电离气体气泡正随时间推移而膨胀，并摧毁了其路径上的尘埃。理解为何被扫掠的气体具有环状和壳状的复杂结构（这是行星状星云的常见特征）仍是一项正在进行的研究工作。

The bubble of ionised gas, which forms the lion’s face, is expanding over time and destroying dust that is in its path. Understanding the reason for why the swept-up gas has a complex structure of rings and shells, a common feature in planetary nebulae, is an ongoing endeavor.

狮子的鬃毛是尘埃壳（dust shell）的内部，正被中心的白矮星照亮。这些看起来像彗尾（cometary tail）物质的毛簇，是幸免于恒星核心辐射的致密尘埃团，它们保护着其后方的物质。

The mane of the lion is the interior of a dust shell that is being illuminated by the white dwarf at the centre. The tufts of hair, which look like cometary tails of material, are compact clumps of dust that have survived the stellar core’s radiation and are protecting the material that lies behind them.

韦布望远镜的图像将这个行星状星云“冻结”在时间中，尽管恒星的死亡及其剧烈的影响仍在继续。随着气体和尘埃从恒星核心向外迁移，NGC 2392将继续发生变化。天文学家（astronomer）估计，这头“狮子”最终将在约10,000年后消散——在天文学尺度上，这是一个相对较短的时间。

Webb’s imagery “freezes” this planetary nebula in time, though the star's death, and its tumultuous effects, go on. NGC 2392 will continue to undergo changes as its gas and dust migrate away from the stellar core. Astronomers estimate that the lion will eventually disperse in approximately 10,000 years — a relatively short period in astronomical terms.

图注：行星状星云NGC 2392，也被称为狮子星云，背景是漆黑的太空。星云位于中心，呈圆形，看起来像雄狮的头部。最中心是一个带有八角衍射尖峰的粉白色小圆点，即一颗白矮星。恒星周围是淡紫粉色的空洞气泡和壳状环。气泡和壳层共同形成了一个椭圆形，顶部附近有两个小而宽的弧线，让人联想到狮子的脸和耳朵。从狮子脸部向外延伸的似乎是一个厚厚的紫蓝色物质环。环的宽度保持一致，看起来像鬃毛。

[Image description: Planetary nebula NGC 2392, also called the Lion Nebula, against the black background of space. The nebula is in the centre, circular in shape, and looks like a male lion’s head. In the very centre is a small, pinkish-white circle with eight-point diffraction spikes, a white dwarf star. Surrounding the star are light purple-pink cavernous bubbles and shell-like rings. The bubbles and shells collectively form an oval with two small, wide arcs near the top, reminiscent of a lion’s face and its ears. What appears to be extended outward from the lion’s face is a thick ring of purple-blue material. The width of the ring is consistent throughout and resembles a mane.]

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