蛇妖星云

2023年3月17日

The Medusa Nebula
Image Credit & Copyright: Martin Bradley Chesterfield Astronomical Society

Explanation: Braided and serpentine filaments of glowing gas suggest this nebula’s popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa’s transforming star is the faint one near the center of the overall bright crescent shape. In this deep telescopic view, fainter filaments clearly extend below and right of the bright crescent region. The Medusa Nebula is estimated to be over 4 light-years across.

Tomorrow’s picture: supernova’s prelude

蛇妖星云
图像提供与版权: Martin Bradley Chesterfield Astronomical Society

说明: 形如纠结长蛇的辉光云气，为这团星云博得蛇妖星云的称号。亦名为Abell 21的蛇妖星云，是一团1,500光年远、位于双子座方向的古老的行星状星云。而就如同名的神话人物一样，这团星云也经历过剧烈的变形。行星状星云是太阳这类小质量恒星演化的最后阶段，它们由红巨星变成炽热白矮星的过程中，会抛出外层气壳。炽热中心星的紫外辐射，则驱动星云发出辉光。而蛇妖星云历经剧变的中心星，其实是位在眉月亮区中心附近那颗较暗的恒星。在这幅望远镜深空图像里，可清楚见到向明亮眉月区右下方伸展的暗淡云气丝。蛇妖星云的宽度估计在4光年以上。（Medusa Nebula蛇妖星云、梅杜莎星云）

明日的图片: supernova’s prelude