2026年1月22日
LDN 1622: Dark Nebula in Orion
Image Credit & Copyright: Chris Fellows
Explanation: The silhouette of an intriguing dark nebula inhabits this cosmic scene. Lynds’ Dark Nebula (LDN) 1622 appears against a faint background of glowing hydrogen gas only visible in long telescopic exposures of the region. In contrast, a brighter reflection nebula, vdB 62, is more easily seen just above the dusty dark nebula. LDN 1622 lies near the plane of our Milky Way Galaxy, close on the sky to Barnard’s Loop, a large cloud surrounding the rich complex of emission nebulae found in the Belt and Sword of Orion. With swept-back outlines, the obscuring dust of LDN 1622 is thought to lie at a similar distance, perhaps 1,500 light-years away. At that distance, this 3 degree wide field of view would span about 100 light-years. Young stars do lie hidden within the dark expanse and have been revealed in Spitzer Space telescope infrared images. Still, the foreboding visual appearance of LDN 1622 inspires its popular name, the Boogeyman Nebula.
Tomorrow’s picture: the faint and mostly round
猎户座中的暗星云LDN 1622
影像提供与版权: Chris Fellows
说明: 在这幅宇宙景象中，一团引人入胜的暗星云轮廓若隐若现。林茨暗星云LDN 1622映衬在微弱发光的氢气背景之前，而这些氢气仅能在对该区域进行长时间望远镜曝光时才能看到。相较之下，位于尘埃暗星云上方不远处，一个更为明亮的反射星云vdB 62则更容易被观测到。LDN 1622位于银河系盘面附近，在天球上的位置接近巴纳德环（Barnard’s Loop）——一个环绕猎户座腰带和宝剑区域发射星云群的巨大星云团。由于其外缘呈现出仿佛被扫掠过的轮廓，天文学家推测，遮蔽视线的尘埃云与巴纳德环处在相近的距离，约为1,500光年。在这样的距离下，视野宽达3度的观测范围，实际上相当于横跨约100光年的空间尺度。虽然在可见光下，LDN 1622显得阴暗而神秘，但其中仍隐藏着年轻的恒星，它们已透过斯皮策太空望远镜的红外线影像被发现。然而，这片暗星云阴郁而诡谲的视觉影像，也正是它获得「恶灵星云（Boogeyman Nebula）」这个名称的由来。
明日的图片: the faint and mostly round
