NASA, ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain); Acknowledgment: Davide De Martin (ESA/Hubble)
Pismis 24, the star cluster seen here in an image released on Dec. 11, 2006, lies within the much larger emission nebula called NGC 6357, located about 8,000 light-years from Earth. The brightest object in the picture was once thought to be a single star with an incredibly large mass of 200 to 300 solar masses. That would have made it by far the most massive known star in the galaxy and would have put it considerably above the currently believed upper mass limit of about 150 solar masses for individual stars. Measurements from NASA’s Hubble Space Telescope, however, discovered that Pismis 24-1 is actually two separate stars, and, in doing so, “halved” their mass to around 100-150 solar masses each.
Image credit: NASA, ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain); Acknowledgment: Davide De Martin (ESA/Hubble)
NASA, ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain); 鸣谢: Davide De Martin (ESA/Hubble)
这张于2006年12月11日发布的图像中所见的恒星团Pismis 24，位于一个更为庞大的发射星云——NGC 6357 之中，距离地球约8,000光年。图中最明亮的天体曾一度被认为是一颗质量极大的单颗恒星，其质量估计高达太阳质量的200到300倍。如果这一估计成立，它将成为银河系中已知质量最大的恒星，远远超过目前广泛接受的单颗恒星质量上限——约为150个太阳质量。
然而，美国国家航空航天局（NASA）的哈勃太空望远镜的观测表明，Pismis 24-1实际上是由两颗彼此相邻的恒星组成。这一发现将此前的质量估计“对半”分开，使每颗恒星的质量降至大约100至150个太阳质量之间。
图片来源: NASA, ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain); 鸣谢: Davide De Martin (ESA/Hubble)
