彗星、鲸鱼与曲棍球棒
The Comet, the Whale, and the Hockey Stick
Image Credit & Copyright: Grand Mesa Observatory, Terry Hancock / Tom Masterson
Explanation: Closest to the Sun on March 1, and closest to planet Earth on April 23, this Comet ATLAS (C/2020 R4) shows a faint greenish coma and short tail in this pretty, telescopic field of view. Captured at its position on May 5, the comet was within the boundaries of northern constellation Canes Venatici (the Hunting Dogs), and near the line-of-sight to intriguing background galaxies popularly known as the Whale and the Hockey Stick. Cetacean in appearance but Milky Way sized, NGC 4631 is a spiral galaxy seen edge-on at the top right, some 25 million light-years away. NGC 4656/7 sports the bent-stick shape of interacting galaxies below and left of NGC 4631. In fact, the distortions and mingling trails of gas detected at other wavelengths suggest the cosmic Whale and Hockey Stick have had close encounters with each other in their distant past. Outbound and only about 7 light-minutes from Earth this Comet ATLAS should revisit the inner solar system in just under 1,000 years.
Tomorrow’s picture: and the Hat
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彗星、鲸鱼与曲棍球棒
影像提供与版权: Grand Mesa Observatory, Terry Hancock / Tom Masterson
说明: 在这幅美丽的望远镜影像里，于3月1日行进到近日点、并在4月23日来到最近地球位置的亚特拉斯彗星（C/2020 R4），头顶泛绿彗发并曳着短尾。在5月5日拍照时，这颗彗星位在猎犬座之内，方位离名为鲸鱼与曲棍球棒的背景星系不远。形似鲸鱼但大小和银河系相当的NGC 4631，是影像右上角，离我们约2千5百万光年远的侧向螺旋星系。在NGC 4631的左侧，可见到形如弯曲棒子的互扰星系对NGC 4656/7。在其他波段侦测到的变形和纠缠的气体尾，指出鲸鱼星系和曲棍球棒星系，在遥远的过去曾近距离接近过。目前逐渐远去但离地球仍然只有7光分远的亚特拉斯彗星，预期会在1,000年内重返太阳系内围。 （Comet ATLAS（C/2020 R4） 亚特拉斯彗星）
明日的图片: and the Hat
