星空有约｜第三位“星际访客”正加速靠近太阳

Core Points - The interstellar visitor 3I/ATLAS is approaching the Sun and is expected to pass its perihelion around October 29, after which it will gradually move away from the solar system [1][4][7] - 3I/ATLAS was discovered in early July when it was approximately 670 million kilometers from the Sun, traveling at a speed of about 61.3 kilometers per second [4][7] - As it approaches the Sun, its speed has increased to approximately 63.1 kilometers per second, and it is now about 420 million kilometers away [4][7] - By the time it reaches perihelion, its distance from the Sun will shrink to about 200 million kilometers, with a speed of around 68 kilometers per second [7] - The closest approach to Earth will be over 240 million kilometers, posing no threat to the planet [7] - 3I/ATLAS is classified as a comet due to its active nature, with a nucleus diameter estimated to be no more than 5.6 kilometers [10][14] - The brightness of 3I/ATLAS has increased from 18th magnitude at discovery to approximately 16.3, with expectations to reach around 14.3 at perihelion [10] - The scientific value of 3I/ATLAS is significant, providing a unique opportunity to study the composition of exoplanets and the processes of planet formation [14]