Li Ye, Li Bin, Hsu Weibiao, Jull A J Timothy, Liao Shiyong, Zhao Yuhui, Zhao Haibin, Wu Yunhua, Li Shaolin, Tang Chipui
Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, China.
CAS Center for Excellence in Comparative Planetology, Hefei, China.
Sci Adv. 2022 Jun 24;8(25):eabm8890. doi: 10.1126/sciadv.abm8890.
Meteoroids/asteroids could deposit energy to Earth during their entries, which arouses great concerns. Strewn field, as a product of meteoroids/asteroids breakup, comprehensively reflects the trajectory, dynamics, and physical properties of meteoroids/asteroids. It typically has a length of several to a dozen kilometers. Nevertheless, the recently found massive Aletai irons in the northwest China comprise the longest known strewn field of ~430 kilometers. This implies that the dynamics of Aletai could be unique. Petrographic and trace elemental studies suggest that all the Aletai masses exhibit unique compositions (IIIE anomalous), indicating that they were from the same fall event. Numerical modeling suggests that the stone skipping-like trajectory associated with a shallow entry angle (e.g., ~6.5° to 7.3°) is responsible for Aletai's exceptionally long strewn field if a single-body entry scenario is considered. The stone skipping-like trajectory would not result in the deposition of large impact energy on the ground but may lead to the dissipation of energy during its extremely long-distance flight.
流星体/小行星在进入地球大气层的过程中会释放能量，这引发了人们的高度关注。散落场作为流星体/小行星解体的产物，全面反映了流星体/小行星的轨道、动力学和物理特性。它的长度通常为几公里到十几公里。然而，最近在中国西北部发现的大量阿勒泰铁陨石包含了已知最长的散落场，约430公里。这意味着阿勒泰的动力学可能是独特的。岩石学和微量元素研究表明，所有阿勒泰陨石都具有独特的成分（III E异常），表明它们来自同一次陨落事件。数值模拟表明，如果考虑单体进入的情况，与浅入射角（例如约6.5°至7.3°）相关的类似石块跳跃的轨道是阿勒泰超长散落场的原因。类似石块跳跃的轨道不会在地面上沉积大量撞击能量，但可能会在其极长距离飞行过程中导致能量耗散。
