Flux of micrometeoroids: lunar sample analyses compared with flux model.

From an analysis of trace element abundances in lunar soils, the influx of meteoritic mass into the lunar surface has recently been estimated by Keays et al. (1) as 3.8 X 10-9 gcm-2 yr-1 and later by Ganapathy et al. (2) as 4 X 10-9 g cm-2 yr-1. I shall show in this note that these numbers are in agreement with independent estimates of the mass distribution for cometary meteoroids. Using the results of satellite penetration measurements and ground observation of meteors, I have recently derived a best estimate of the meteoroid mass distribution (3). Accordingly, the flux of meteoroids into the earth's atmosphere per square meter per second per 27r sterad in the mass range from m to m + dm kg is given by