Evaporation of high speed sporadic meteors

[摘要] Recent measurements conducted at the Arecibo Observatory report high-speedsporadic meteors having velocities near 50 km/s. The results seem toindicate a bimodal velocity distribution in the sporadic meteors (maxima at~20 km/s and ~50 km/s). The particles have a maximum mass of~1µg. This paper will present an analysis of the ablation of 1µgmeteoroids having velocities of 20, 30, 50, and 70 km/s. Thecalculations show that there is fractionation even for the fast meteoroids,the effect being particularly noticeable for the 1µg sporadicparticles, and less so for the heavier particles. The relevance of thecalculations to the radar observations of the sporadic meteors will bediscussed.

[学科分类] 大气科学