项链星云的喷流
Jets from the Necklace Nebula
Image Credit: ESA, Hubble, NASA; Processing: K. Noll
Explanation: What celestial body wears the Necklace Nebula? First, analyses indicate that the Necklace is a planetary nebula, a gas cloud emitted by a star toward the end of its life. Also, what appears to be diamonds in the Necklace are actually bright knots of glowing gas. In the center of the Necklace Nebula are likely two stars orbiting so close together that they share a common atmosphere and appear as one in the featured image by the Hubble Space Telescope. The red-glowing gas clouds on the upper left and lower right are the results of jets from the center. Exactly when and how the bright jets formed remains a topic of research. The Necklace Nebula is only about 5,000 years old, spans about 5 light years, and can best be found with a large telescope toward the direction of the constellation of the Arrow (Sagitta).
Tomorrow’s picture: jellyfish in space
项链星云的喷流
影像提供: ESA, Hubble, NASA; 影像处理: K. Noll
说明: 那种天体会挂着项链呢？首先，分析指出项链星云是个行星状星云，是一颗恒星在生命末期所抛出的气体云。此外，项圈上看似钻石的结构，其实是正在散发明亮辉光的物质结。这幅哈勃太空望远镜主题影像所呈现的项链星云，中心看似只有单颗恒星，但它可能是2颗极端密近、并共享大气层的互绕恒星。而影像左上及右下的泛红气体云，则是受到源自中心的喷流激发而发光现身的天体。不过究竟这些明亮喷流是如何形成的，至今仍是研究的题材。如想观赏年龄5,000多年、宽约5光年的项链星云，最佳的方式是用大望远镜巡礼北天的天箭座。
明日的图片: jellyfish in space
