NGC 6888: 眉月星云
NGC 6888: The Crescent Nebula
Image Credit & Copyright: Team ARO
Explanation: How was the Crescent Nebula created? Looking like an emerging space cocoon, the Crescent Nebula, visible in the center of the featured image, was created by the brightest star in its center. A leading progenitor hypothesis has the Crescent Nebula beginning to form about 250,000 years ago. At that time, the massive central star had evolved to become a Wolf-Rayet star (WR 136), shedding its outer envelope in a strong stellar wind, ejecting the equivalent of our Sun’s mass every 10,000 years. This wind impacted surrounding gas left over from a previous phase, compacting it into a series of complex shells, and lighting it up. The Crescent Nebula, also known as NGC 6888, lies about 4,700 light-years away in the constellation of Cygnus. Star WR 136 will probably undergo a supernova explosion sometime in the next million years.
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NGC 6888: 眉月星云
影像提供与版权: Team ARO
说明: 眉月星云是如何形成的？位于这幅主题影像中心处、形似破裂太空巨蛹的眉月星云，是由其中心的亮星所产生的。最可信的起源假说认为，眉月星云大约在25万年前开始成形。当时，其中心的大质量恒星已经演化成沃尔夫-拉叶星（WR 136），并以强烈恒星风的方式抛弃其外层，大约每1万年就释出相当于1个太阳的质量。它的恒星风推挤先前演化阶段留下的气体，把它们压缩成一个个复杂的壳层，并激发它们发光。眉月星云（NGC 6888）位于天鹅 座方向约4,700光年远处。在接下来的一百万年内，恒星WR 136或许会发生超新星爆炸。
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