彗星C/2017 K2（PanSTARRS）

2022年6月30日

Comet C/2017 K2 (PanSTARRS)
Image Credit & Copyright: Jose J. Chambo (Cometografia)

Explanation: Imaged on June 20 2022, comet C/2017 K2 (PanSTARRS) shares this wide telescopic field of view with open star cluster IC 4665 and bright star Beta Ophiuchi, near a starry edge of the Milky Way. On its maiden voyage to the inner Solar System from the dim and distant Oort cloud, this comet PanSTARRS was initially spotted over five years ago, in May 2017. Then it was the most distant active inbound comet ever found, discovered when it was some 2.4 billion kilometers from the Sun. That put it between the orbital distances of Uranus and Saturn. Hubble Space Telescope observations indicated the comet had a large nucleus less than 18 kilometers in diameter. Now visible in small telescopes C/2017 K2 will make its closest approach to planet Earth on July 14 and closest approach to the Sun this December. Its extended coma and developing tail are seen here at a distance of some 290 million kilometers, a mere 16 light-minutes away.

Tomorrow’s picture: solar system trails

彗星C/2017 K2（PanSTARRS）
影像提供与版权：Jose J. Chambo (Cometografia)

说明：在2022年6月22日拍摄这幅大视野望远镜影像之时，位在银河恒星密布盘面边缘的彗星C/2017 K2 (PanSTARRS)，与疏散星团IC 4665及亮星宗正一（Beta Ophiuchi蛇夫座）分享这片视野。这颗来自遥远昏暗奥尔特云、首次进入太阳系内围的PanSTARRS彗星，发现于5年多前的2017年5月。当时它位在天王星与土星的轨道之间，距离太阳约有24亿公里，创下冲向内围活跃彗星的最远发现记录。哈伯太空望远镜的观测显示，这颗彗星有个小于18公里直长径的大彗核。目前用小望远镜即可见的C/2017 K2，将在7月14日行进到最近地球的位置，然后在今年的12月抵达近日点。在拍摄这幅影像时，它距离我们约2亿9千万公里远，其弥漫的彗发和伸展中的彗尾近在16光分之外。

明日的图片: solar system trails