Sizes and Masses of Satellite Observed Meteoroids

Abstract

Influx of meteoroids onto Earth is reasonably well known for sizes of up to about 1 meter applying results from three independent Photographic Bolide (Fireball) Networks. The change of cumulative numbers with increasing mass was recently improved by new calibration at 100 kg masses from a very self-consistent solution for motion and ablation of the Lost City bolide (bulk density and terminal mass known from the recovered meteorite). The influx onto Earth of small asteroids observed in reflected sunlight is also reasonably well established from observations of the Space-Watch Telescope down to sizes of somewhat less than 10 meters. Cumulative fluxes as function of total kinetic energy at entry of these bodies into the Earth's atmosphere are used as standards for comparison with relative fluxes derived from cumulative numbers of 21 meteoric events observed by satellites (SA bolides). Absolute calibration is realized by comparing cumulative numbers of 43 Prairie Network (PN) bolides brighter than absolute magnitude –10 with the same flux curve and using the same method. Dynamically determined masses of the 43 PN bolides are used to define the mass scale of the satellite-observed (SA) bolides. Definitions of differential and total luminous efficiency are presented, and data on total luminous efficiencies as well as on velocities, masses, ablation coefficients, and on total radiated energies of 33 PN bolides are given. For the average luminous efficiency, the masses of the SA bolides resulted between 6 x 10 6 kg and 3500 kg with the median value of 80000 kilograms. Corresponding sizes are from 15 m to 1.2 m with the median at 3.4 m.