PERSEID METEOROIDS - THE RELATIONSHIP BETWEEN MASS AND ORBITAL SEMIMAJOR AXIS

By the analysis of photographic Perseid meteor orbital data the semimajor axis of the causative meteoroids is found not to vary systematically as a function of meteoroid mass over the mass range 0.001 < m < 30 g. The only way that this finding is compatible with the Whipple formula for the meteoroid ejection velocity from a cometary nucleus is if the meteoroids have densities which vary as a function of mass. The radius-density product is about 0.23 +/- 0.05 g cm(-2).