2025年7月17日
3I/ATLAS
Image Credit: Gemini Observatory/NOIRLab/NSF/AURA/K. Meech (IfA/U. Hawaii)
Processing: Jen Miller, Mahdi Zamani (NSF/NOIRLab)
Explanation: Discovered on July 1 with the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert, System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is so designated as the third known interstellar object to pass through our Solar System It follows 1I/ʻOumuamua in 2017 and the comet 2I/Borisov in 2019. Also known as C/2025 N1, 3I/ATLAS is clearly a comet, its diffuse cometary coma, a cloud of gas and dust surrounding an icy nucleus, is easily seen in these images from the large Gemini North telescope on Maunakea, Hawai‘i. The left panel tracks the comet as it moves across the sky against fixed background stars in successive exposures. Three different filters were used, shown in red, green, and blue. In the right panel the multiple exposures are registered and combined to form a single image of the comet. The comet’s interstellar origin is also clear from its orbit, determined to be an eccentric, highly hyperbolic orbit that does not loop back around the Sun and will return 3I/ATLAS to interstellar space. Not a threat to planet Earth, the inbound interstellar interloper is now within the Jupiter’s orbital distance of the Sun, while its closest approach to the Sun will bring it just within the orbital distance of Mars.
Tomorrow’s picture: pixels in space
彗星3I/ATLAS
影像提供: Gemini Observatory/NOIRLab/NSF/AURA/K. Meech (IfA/U. Hawaii)
影像处理: Jen Miller, Mahdi Zamani (NSF/NOIRLab)
说明: 位于智利里奥胡鲁塔多（Rio Hurtado）、由美国航空航天局资助的ATLAS（小行星地球撞击最后警报系统）巡天望远镜，在今年7月1日发现的彗星3I/ATLAS，其名称反映了它是第三颗穿过我们太阳系的星际天体。而先前的二颗星际天体，则分别是2017年的斥候星（1I/ʻOumuamua）及2019年的博里索夫彗星（2I/Borisov）。在这些由位于夏威夷基亚山的北双子望远镜所拍摄的影像里，亦名为C/2025 N1的3I/ATLAS，明显拥有气体及尘埃组成的弥漫彗发，因此显然是一颗彗星。左侧图板的红、绿、蓝波段影像数据，呈现了这颗彗星在背景恒星之间移动的轨迹。右侧图板则是将这些数据对齐叠加后，组合出的清晰彗星影像。从它的运动轨迹得以确认，彗星3I/ATLAS具有高离心率的双曲线轨迹，因此它不会绕太阳转圈，而是会回到星际空间。这颗来自太阳系外的闯入者，已来到木星的轨道之内，在最靠近太阳时，预期会行进到火星的轨道内，但并不会对地球造成威胁。
明日的图片: pixels in space
