星空有约｜起底太阳系第三位“闯入者”的“身世”

Core Viewpoint - The discovery of the interstellar object 3I/ATLAS, the third known visitor to the solar system, has garnered significant attention from astronomers and enthusiasts worldwide [1][4]. Group 1: Characteristics of 3I/ATLAS - 3I/ATLAS is classified as an interstellar object due to its high eccentricity hyperbolic trajectory, with an eccentricity of 6.23, differing from the elliptical or near-parabolic orbits of typical solar system bodies [3]. - The object is believed to have a cold nucleus and exhibits cometary activity, suggesting it is more likely a comet than an asteroid [3]. - At the time of discovery, 3I/ATLAS was approximately 670 million kilometers from the Sun and had a brightness of about magnitude 18, making it difficult to observe with standard telescopes [4]. Group 2: Observational Opportunities and Future Trajectory - Ground-based telescopes are expected to observe 3I/ATLAS until September, after which it will be too close to the Sun for observation [5]. - The object is predicted to reach its perihelion around October 29, entering the orbit of Mars, and will maintain a distance of at least 240 million kilometers from Earth [4]. - Following its perihelion, 3I/ATLAS is expected to gradually move away from the solar system and return to interstellar space over the coming years [5]. Group 3: Historical Context of Interstellar Visitors - Prior to 3I/ATLAS, the first known interstellar visitor was 'Oumuamua, discovered in October 2017, which was initially thought to be an asteroid but later classified as a comet [5]. - The second interstellar visitor, 2I/Borisov, was discovered in 2019 and is also classified as a comet [5]. - The rarity of interstellar objects entering the solar system highlights the unique nature of such discoveries and the ongoing research into their origins [5].