小行星99942 Apophis与已知小行星目录的交会情况
Encounter circumstances of asteroid 99942 Apophis with the catalogue of known asteroids
AI总结：
本研究排查截至2029年已知小行星与Apophis的轨道交会，发现其2026年将与4544 Xanthus近距离相遇，并指出其他需监测对象。
AI中文摘要：
小行星99942 Apophis将于2029年4月在地球附近掠过。预计它会以安全距离错过我们的星球，但如果在此期间Apophis的轨道因与另一颗小行星相撞而受到扰动，这一情况可能改变。尽管这种碰撞的统计概率极小，但与Apophis相关的高风险促使我们研究即使是这种极不可能发生的情形。在本研究中，我们识别了截至2029年4月已知小行星与Apophis之间的交会。我们在此表明，Apophis将于2026年12月与直径1300米的小行星4544 Xanthus交会。它们的最小轨道交会距离（MOID）小于10,000公里，而Xanthus仅在Apophis之后四小时经过该最近点。虽然直接碰撞已被排除，但这次交会足够接近，伴随Xanthus的物质（如果存在）可能撞击Apophis。我们还识别了其他值得监测的小行星交会。
英文摘要：
Asteroid 99942 Apophis will pass near the Earth in April 2029. Expected to miss our planet by a safe margin, that could change if Apophis' path was perturbed by a collision with another asteroid in the interim. Though the statistical chance of such a collision is minuscule, the high risk associated with Apophis motivates us to examine even this very unlikely scenario. In this work, we identify encounters between known asteroids and Apophis up to April 2029. Here we show that Apophis will encounter the 1300 meter diameter asteroid 4544 Xanthus in December 2026. Their Minimum Orbit Intersection Distance (MOID) is less than 10,000 km, with Xanthus passing that closest point just four hours after Apophis. Though a direct collision is ruled out, the encounter is close enough that material accompanying Xanthus (if any) could strike Apophis. We also identify other asteroid encounters that deserve monitoring.
