小行星35633和135356的历表研制及密近交会前后的轨道演化

在已知(349)Dembowska高精度质量的情况下,通过考虑密近交会改进了小行星35633和135356的历表.本文由蒙特卡罗方法给出了改进历表的不确定度,并利用姚安高精度望远镜的观测数据验证了历表改进的可靠性.与未考虑密近交会因素的JPL历表比较的结果表明,两种轨道之间瞬时根数的差值在密近交会时刻附近快速变化,这体现了(349)Dembowska在交会中对天体轨道演化的影响.尽管这种影响在一定时间内并不会产生显著的观测效应,但在历表研制中不予以考虑会显著降低外推历表位置的精度.

Ephemeris development for asteroids 35633 and 135356 and their orbital evolution induced by a close encounter

Based on the newly determined mass of(349)Dembowska,the ephemerides of two asteroids(35633 and 135356)were improved by taking into account the effects of their close encounter with(349)Dembowska.A Monte-Carlo method was used to determine the time-dependent uncertainty of the ephemerides.Reliability of the improvements were verified based on the observations from the Yaoan High Precision Telescope.The improved ephemerides were compared with those provided by Jet Propulsion Laboratory(JPL),for which the effects of close encounters were not considered.The results show that rapid and significant orbital evolution presents in a short time interval around the instant of the closest approach between the encountering bodies,which represents the effects of(349)Dembowska.Even though the effects will not be detectable by ground-based observations in a certain time,the extrapolation accuracy of ephemerides will decrease significantly without considering the effects when developing ephemerides.