星际空间来的博里索夫彗星

2019 December 14

Interstellar Comet 2I/Borisov
Image Credit: NASA, ESA, and D. Jewitt (UCLA) et al.

Explanation: From somewhere else in the Milky Way galaxy, Comet 2I/Borisov is just visiting the Solar System. Discovered by Crimean amateur astronomer Gennady Borisov on August 30, 2019, the first known interstellar comet is captured in these two recent Hubble Space Telescope images. On the left, a distant background galaxy near the line-of-sight to Borisov is blurred as Hubble tracked the speeding comet and dust tail about 327 million kilometers from Earth. At right, 2I/Borisov appears shortly after perihelion, its closest approach to Sun. Borisov’s closest approach to our fair planet, a distance of about 290 million kilometers, will come on December 28. Even though Hubble’s sharp images don’t resolve the comet’s nucleus, they do lead to estimates of less than 1 kilometer for its diameter.

星际空间来的博里索夫彗星
影像提供: NASA, ESA, and D. Jewitt (UCLA) et al.

说明: 来自银河系某处的博里索夫彗星（2I/Borisov），目前正在造访太阳系。这二幅最近由哈伯太空望远镜拍摄的影像，记录了克里米亚业余天文学家博里索夫发现于8月30日，首颗获得确认的星际彗星。在上左图里，一个位在博里索夫彗星视线方向的背景星系，因为影像拍摄是以这颗当时距离约3亿2千7百万公里远，快速移动的彗星和尘埃尾为导星标的，而显著模糊晕开。上右图，则呈现刚通近日点的博里索夫彗星。博里索夫彗星将在12月28日，行进到最靠近地球，距离约2亿9千万公里远的位置。虽然哈伯的清晰影像，并未能解析出彗星的彗核，然而据而估计出的直径为小于1公里。