2025年1月20日
Comet ATLAS Rounds the Sun
Image Credit: NASA, SOHO Spacecraft, LASCO C3; Processing: Rolando Ligustri
Explanation: Why does Comet ATLAS have such colorful tails? Last week Comet C/2024 G3 (ATLAS) passed its closest to the Sun — well inside the orbit of Mercury — and brightened dramatically. Unfortunately, the comet was then so angularly near the Sun that it was very hard for humans to see. But NASA’s SOHO spacecraft saw it. Pictured is a SOHO (LASCO C3) image of Comet ATLAS that is a composite of several different color filters. Of the several tails visible, the central white tails are likely made of dust and just reflecting back sunlight. The red, blue, and green tails are likely ion tails with their colors dominated by light emitted by specific gases that were ejected from the comet and energized by the Sun. Currently, Comet ATLAS is showing long tails in southern skies but fading as it moves out of the inner Solar System.
Growing Gallery: Comet ATLAS (G3)
Tomorrow’s picture: long tails
阿特拉斯彗星绕过太阳
影像提供: NASA, SOHO Spacecraft, LASCO C3; 影像处理: Rolando Ligustri
说明: 为何阿特拉斯彗星的彗尾如此多彩？在上星期，阿特拉斯彗星（Comet C/2024 G3 ATLAS）彗星来到深在水星轨道之内的近日点，并戏剧性的增亮。很遗憾的，此彗星与太阳的分离角太小，使得人类用肉眼难以直接观看。不过，美国国家航空航天局的SOHO观日卫星，倒是捕捉到它的身影。这幅SOHO卫星的LASCO C3日冕仪影像，组合了多个不同色彩滤镜的数据。影像里，阿特拉斯彗星的多条彗尾之中，中央泛白的长尾，可能是反射阳光的尘埃尾。而红、蓝与绿等色泽的彗尾，则可能是彗星释出的特定气体受到阳光的电离激发而发光，所以是离子尾。目前，曳着长长彗尾的阿特拉斯彗星位于南半球的天空中，不过随着它缓缓远离太阳系内围，其亮度也逐渐衰减。
不断扩大的画廊: 阿特拉斯彗星
明日的图片: long tails
