美丽的三叶星云

2022年8月5日

A Beautiful Trifid
Image Credit & Copyright: Vikas Chander

Explanation: The beautiful Trifid Nebula is a cosmic study in contrasts. Also known as M20, it lies about 5,000 light-years away toward the nebula rich constellation Sagittarius. A star forming region in the plane of our galaxy, the Trifid does illustrate three different types of astronomical nebulae; red emission nebulae dominated by light from hydrogen atoms, blue reflection nebulae produced by dust reflecting starlight, and dark nebulae where dense dust clouds appear in silhouette. But the red emission region, roughly separated into three parts by obscuring dust lanes, is what lends the Trifid its popular name. Pillars and jets sculpted by newborn stars, above and right of the emission nebula’s center, appear in famous Hubble Space Telescope close-up images of the region. The Trifid Nebula is about 40 light-years across. Too faint to be seen by the unaided eye, it almost covers the area of a full moon in planet Earth’s sky. Open star cluster M21 just peeks into this telescopic field of view along the bottom right edge of the frame.

Tomorrow’s picture: the grooved moon of Mars

美丽的三叶星云
影像提供与版权: Vikas Chander

说明: 美丽的三叶星云是研究宇宙天体对比的好标的。亦称为M20的三叶星云，位在星云拥挤的人马座内，离我们约有5,000光年远。三叶星云是位在我们银河系盘面上的恒星形成区之一，同时拥有三种基本形态的天文星云：被氢原子辉光渲染成红色的发射星云、尘埃反射星光所形成的泛蓝反射星云、以及名为暗星云的致密尘埃云之剪影。此外，在不透光的尘埃带之切割下，明亮的发射星云被分割成不等的三片，为它博得三叶星云的俗名。在发射星云中心的中右上方，有新生恒星发出的喷流和所雕塑出的云气柱，这些因哈勃太空望远镜为此区拍摄的特写影像而声名大噪的天体。宽约40光年、于地球天空的张角与满月相当的三叶星云，是肉眼不得见的昏暗天体。此外，在这片望远镜视野的下右缘，可见到疏散星团M21。

明日的图片: the grooved moon of Mars