2026年2月27日
Sharpless 249 and the Jellyfish Nebula
Image Credit & Copyright: Katelyn Beecroft
Explanation: Normally faint and elusive, the Jellyfish Nebula is caught in this alluring telescopic field of view. Floating in the interstellar sea, the nebula is anchored right and left by two bright stars, Mu and Eta Geminorum, at the foot of the celestial twins. The Jellyfish Nebula itself is right of center, seen as a brighter arcing ridge of emission with dangling tentacles. In fact, this cosmic jellyfish is part of bubble-shaped supernova remnant IC 443, the expanding debris cloud from a massive star that exploded. Light from the explosion first reached planet Earth over 30,000 years ago. Like its cousin in astrophysical waters the Crab Nebula supernova remnant, the Jellyfish Nebula is known to harbor a neutron star, the ultradense remnant of the collapsed stellar core. An emission nebula cataloged as Sharpless 249 fills the field at the upper left. The Jellyfish Nebula is about 5,000 light-years away. At that distance, this image would be about 300 light-years across.
Tomorrow’s picture: light-weekend
夏普勒斯249与水母星云
影像提供与版权: Katelyn Beecroft
说明: 通常暗淡而难以捉摸的水母星云，却被捕捉在这迷人的望远镜视野中。宛若漂浮于星际之海，这团星云两侧由两颗明亮恒星锚定，双子座μ（井宿一 Tejat）与双子座η（钺 Propus），位在双子座（天上的双胞胎）的足下。水母星云本体位于视野中央偏右，呈现出一道明亮的弧形发射脊，伴随垂下触须状的光芒。事实上，这只宇宙水母是气泡状超新星遗迹IC 443的一部分，它是来自一颗大质量恒星爆炸后不断膨胀的残骸云。爆炸产生的光线在3万多年前首次抵达地球。与它在天体物理海洋中的表亲——蟹状星云超新星遗迹一样，水母星云已知藏有一颗中子星，即恒星核心坍缩后形成的超高密度残骸。左上方视野中，还有一团被编录为夏普勒斯249的发射星云铺展其间。水母星云距离地球约5,000光年。以此距离估算，影像涵盖的宽度约为300光年。
明日的图片: light-weekend
