High geocentric velocity meteor ablation

Interstellar origin meteoroids have now been detected using radar, image intensified video, large aperture radar and space dust impact techniques. Dynamical and radiation production mechanisms will eject some meteoroids from other planetary systems into orbits which will impact Earth with high geocentric velocities. In this paper we numerically model the ablation of high geocentric velocity ( 71 to 500 km s(-1)) meteors in order to predict the heights, light curves and trail lengths to be expected. We modeled three compositions and structures: asteroidal, cometary and porous cometary. Meteoroid masses ranging from 10(-6) to 10(-13) kg were used in the model. As expected, these high geocentric velocity meteors, when compared to other meteors, ablate higher in the atmosphere. For example a 300 km s(-1) cometary structure meteor of mass 10(-9) kg will have a peak luminosity at about 190 km. They will also have significantly longer trail lengths. The same 300 km s(-1), 10(-9) kg cometary meteor would be within 2 mag of its peak brightness for a vertical displacement of 60 km if incident at a zenith angle of 45 degrees. The peak light intensity of these high geocentric velocity meteors changes only slowly with velocity. Although the incident kinetic energy per unit time increases dramatically, this is largely offset by a decrease in the optical luminous effciency in this velocity regime according to our luminous efficiency model. The 300 km s(-1), 10(-9) kg cometary meteor would have an absolute meteor magnitude at peak luminosity of about +8.5 mag. Our results suggest that at least those high geocentric velocity meteors larger than about 10(-8) kg should be observable with current meteor electro-optical technology although there may be observational biases against their detection. The results of this paper can be used to help optimize a search strategy for these very high geocentric velocity meteors.