Frictional and radiation heating of micron-sized meteoroids in the Earth's upper atmosphere

Abstract

This paper follows on from earlier work presented on the dynamics of micron-sized meteoroid particles, as they are decelerated in the Earth's atmosphere at heights of 100 km or greater. Here the heating effects on these meteoroids are examined; both the intense heating during deceleration and the temperatures reached by particles settling through the atmosphere with low speeds ∼cm s-1 are considered. Meteoroid deceleration by sputtering of molecules from the surface is shown to provide a mechanism by which small particles can decelerate from high entry speeds down to speeds of the order of cm s-1 while avoiding extreme heating. The question of survivability of organic material on meteoroid bodies in free space and during descent through the Earth's atmosphere is addressed.