2025年8月25日
The Meteor and the Star Cluster
Image Credit & Copyright: Yousif Alqasimi & Essa Al Jasmi
Explanation: Sometimes even the sky surprises you. To see more stars and faint nebulosity in the Pleiades star cluster (M45), long exposures are made. Many times, less interesting items appear on the exposures that were not intended — but later edited out. These include stuck pixels, cosmic ray hits, frames with bright clouds or Earth’s Moon, airplane trails, lens flares, faint satellite trails, and even insect trails. Sometimes, though, something really interesting is caught by chance. That was just the case a few weeks ago in al-Ula, Saudi Arabia when a bright meteor streaked across during an hour-long exposure of the Pleiades. Along with the famous bright blue stars, less famous and less bright blue stars, and blue-reflecting dust surrounding the star cluster, the fast rock fragment created a distinctive green glow, likely due to vaporized metals.
Jigsaw Universe: Astronomy Puzzle of the Day
Tomorrow’s picture: leaky star
流星与星团天象
影像提供与版权: Yousif Alqasimi & Essa Al Jasmi
说明: 有时候，天空也会带来意想不到的惊喜。为了观测昴宿星团（M45）中更多的恒星与微弱的星云结构，天文学家通常会进行长时间曝光。不过，在这些照片里，常常会出现一些「不受欢迎的来客」，之后通常都会被删除，例如：坏点像素、宇宙射线击中的痕迹、被云或月光照亮的画面、飞机的光迹、镜头眩光、微弱的人造卫星轨迹，甚至是昆虫飞过的痕迹。然而，有时候也会意外捕捉到真正令人惊艳的画面。就在几周前，沙特阿拉伯的乌拉（al-Ula）拍摄一张昴宿星团的一小时长曝光时，一颗明亮的流星划过了夜空。画面中不仅能看到那些著名的明亮蓝色恒星，还有较暗淡的蓝色星星，以及星团周围反射蓝光的尘埃；而那颗高速划过的岩石碎片，则留下了一道独特的绿色光迹，这很可能是因为其中的金属在大气中气化所造成的。
拼图宇宙: 每日天文学谜题
明日的图片: leaky star
