天文·每日一图——人马三重星云
文摘
2024-07-10 16:28
广东
Image Credit & Copyright: Andy ErmolliExplanation: These three bright nebulae are often featured on telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula above center, and colorful M20 below and left in the frame. The third emission region includes NGC 6559, right of M8 and separated from the larger nebula by a dark dust lane. All three are stellar nurseries about five thousand light-years or so distant. Over a hundred light-years across the expansive M8 is also known as the Lagoon Nebula. M20’s popular moniker is the Trifid. Glowing hydrogen gas creates the dominant red color of the emission nebulae. But for striking contrast, blue hues in the Trifid are due to dust reflected starlight. The broad interstellar skyscape spans almost 4 degrees or 8 full moons on the sky.
说明: 用望远镜巡礼人马座和恒星拥挤的银河中心时，这三个明亮星云经常是拍摄的标的。其实远在十八世纪时，查尔斯·梅西耶就编录了其中的两个星云，它们分别是影像中上方的大星云M8和左下缘附近的美丽M20。第三个发射星云则是M8右方的NGC 6559，二者之间隔着一道黝黑的尘埃带。这三个星云，都是距离在5千光年左右的恒星诞生区。跨幅超过100光年的庞大M8，亦名为礁湖星云，而M20常见的昵称是三叶星云。影像中，明亮氢气云发出的红光，是这些发射星云最主要的色泽，而三叶星云内高反差的泛蓝区域，则来自被尘埃所反射的星光。这片宽广的星际视野，涵盖约4度（8个满月宽度）的天区。
![]()
点击↓↓↓阅读原文，获取原图
点亮小花![]()
告诉大家
喜欢就奖励一个“![]()
”和“在看”
