Astronomy Picture of the Day——沙普利斯249与水母星云
Sharpless 249 and the Jellyfish Nebula
Image Credit & Copyright: SteveMilne & Barry Wilson, Processing - Steve Milne
Explanation: Normally faint and elusive,the Jellyfish Nebula is caught in this alluring telescopic field of view. Theentire scene is a two panel mosaic constructed using narrowband image data,with emission from sulfur, hydrogen and oxygen atoms shown in red, green andblue hues. It's anchored right and left by two bright stars, Mu and EtaGeminorum, at the foot of the celestial twin. The Jellyfish Nebula itself isright of center, the brighter arcing ridge of emission with dangling tentacles.In fact, the cosmic jellyfish is part of bubble-shaped supernova remnant IC443, the expanding debris cloud from a massive star that exploded. Light fromthe explosion first reached planet Earth over 30,000 years ago. Like its cousinin astrophysical waters the Crab Nebula supernova remnant, the Jellyfish Nebulais known to harbor a neutron star, the remnant of the collapsed stellar core.An emission nebula cataloged as Sharpless 249 fills the field at the upperleft. The Jellyfish Nebula is about 5,000 light-years away. At that distance,this image would be about 300 light-years across.
沙普利斯249与水母星云
这幅迷人的照片是望远镜捕捉到的水母星云，因其通常黯淡且不太容易找到，所以这幅图片显得尤其珍贵。整幅图像是由窄带影像数据构建的两张照片拼接而成，其中硫、氢、氧原子的辐射分别呈现出红、绿、蓝色泽。水母星云的左右两侧是两颗亮星——双子座足部的钺和井宿一。水母星云位于影像中央右侧，有一道明亮的弧状发射脊和舞动的触须。实际上，这只宇宙水母是气泡状超新星遗迹IC 443的一部分，这是一颗大质量恒星爆炸后残留的扩张碎片云。超新星爆炸发出的光在3万多年前首次到达地球。就像它在天体物理学水域中的表亲——超新星遗迹蟹状星云一样，水母星云内也含有一颗中子星，它是恒星核崩塌后的残留物。编号为沙普利斯249的发射星云充满在图像左上方的区域。水母星云距离地球约5000光年。以这个距离来计算，该图像覆盖了约300光年的天区。
参考文献：
https://apod.nasa.gov/apod/image/1903/F_JellyFish_FIN_APOD.jpg
近期文章：
Astronomy Picture of the Day——尘埃场内的鸢尾花星云