Tempel-Tuttle彗星与近年的狮子座流星雨  

COMET TEMPEL-TUTTLE AND RECENT LEONID METEOR SHOWER

作　　者：吴光节[1,2,3] 

机构地区：[1]中国科学院云南天文台 [2]中国科学院国家天文观测中心北京100012 [3]中国科学院天文光学联合开放实验室

出　　处：《天文学报》2001年第2期125-133,共9页Acta Astronomica Sinica

基　　金：国家自然科学基金! (批准号 :198730 2 0和 196530 0 1)

摘　　要：对狮子座流星雨的历史进行了回顾和讨论 ,并利用“彗星 地球轨道分离 (CEOS)及地球滞后彗星时间 (TE C)”统计图进行分析 ,发现几乎所有的狮子座流星暴都位于一个倾斜的方框内 .而这一倾斜方框左右边界的斜率大约为 1 5m/s.方框的宽度大约为 4yr.它表明 ,33年一度的狮子座流星雨一般不会有超过 4年的爆发期 .更细致的分析表明 ,最强的流星暴位于一弯曲的细窄条带 .在彗星一次回归期 ,亮流星的比例将逐年衰减 .这些事实 ,可以用运动、碎裂、扩散的尘埃彗尾模型进行解释 .由 1 5m/s速度得到的流星体尺度大小也与事实相容 .并且 ,这表明与地球相遇的流星体粒子是以有限的速度偏离彗星轨道的 .这使得彗星 地球轨道分离 (CEOS)越大 ,能够看到强流星雨所需的地球滞后彗星时间 (TE C)就越长 .由此倾斜方框的存在 ,可以对未来狮子座流星雨进行预报 .表明在 1 998- 2 0 0 0年期间将有较强的狮子座流星雨 ,中心在 1 999年 .至于 2 0 0 0年以后 ,要在 1 0 0多年以后才会有较强的流星暴 .The Leonid meteor shower has the most spectacular burst in history as one of famous meteor showers. Since 1998 a new series of activity of the Leonids has been coming. To predict what will it be in resent years and the future, a review on the appearances of the showers in history is done. Especially, the diagram of CEOS (the Comet Earth Orbits Separation) versus T E C (the time gap of the Earth following the Comet) was analyzed. It is found that on the diagram almost all of the data of CEOS versus T E C of the meteor storms are distributed in an inclined square, moreover the strongest storms in a curved strip. The boundaries of the square have a slope in unit of speed with a value of about 15 m s -1 . The sizes of meteoroids calculated from this velocity are also reasonable. It means that the particles colliding with the Earth have a limiting velocity to drift off its original orbit. The bigger the CEOS was, the longer time gap after the comet passed would be needed for a possible storm. The width of this square indicates the stronger Leonid showers would be never seen longer than about four consecutive years. In one cometary return, the ratio of bright meteors will decrease year by year. These facts could be explained by a model of the formation of a cometary dust tail, including motion, dispersion, and breaking up of the dust particles. Prediction could be got with this square region, it is that we may have Leonid showers only in 1998-2000 with a peak in 1999. After AD 2000 it will be another century before significant displays are once again likely.

关 键 词：流星群 狮子座 流星雨 Tempel-Tuttle彗星 地球轨道 

分 类 号：P185.8[天文地球—天文学]