The system of short period meteor streams

Abstract

AbstractThe orbital characteristics of precisely reduced photographic meteors were studied. Most photographic meteors move in short period, direct orbits with orbital periods inbetween those of Jupiter and Mars. Practically no meteors have (Orbital periods coincident with those of the planets Jupiter, Mars and Earth.A search among all precisely reduced, photographic meteors revealed a number of new – or previously not well studied – meteor streams. For 18 short period meteor streams the scatter in the orbital elements 1/a,πand Ω was studied. An almost linear relation was found between the mean orbital energy of a meteor stream (– 1/a) and the standard deviation σ(1/a), indicating a progressive increase in the orbital scatter with decreasing mean distance to the sun. An index of mean meteoroid density was computed for 11 of the short period streams. The mean density increases with decreasing semi-major axis.The results are interpreted as indicating that the short period meteor streams are initially formed in orbits with periods slightly shorter than Jupiter’s. As the streams gradually drift inwards towards the sun under the influence of various drag forces the individual stream members spread out and only the high density, resistant meteors still remain, or can be recognized, as stream members.