view Abstract Citations (3) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An Analysis of the Atmospheric Trajectories of 413 Precisely-Reduced Photographic Meteors. Jacchia, Luigi G. ; Verniani, Franco F. ; Briggs, Robert E. Abstract The analysis covers the same Super-Schmidt meteors for which orbital data have been analyzed by Jacchia and Whipple (Smithsonian Contrib. Asfrophys. 4, 97, 1961). Heights, lengths, decelerations, and magnitudes are related to such parameters as velocity, angle of incidence, mass, ablation coefficient and fragmentation index; the latter two are in turn related to geometric and physical characteristics. A comparison with classical meteor theory shows again and again that fragmentation is the most important factor in causing the wide discrepancies between theory and observation. We confirm essentially all of Jacchia's results from previously published partial analyses of the same material. In addition we find that fragmentation causes a decrease in the luminous efficiency of meteors. Nevertheless, the maximum brightness of strongly fragmenting meteors is greater than for those which are less fragmentable; Super-Schmidt meteors are, on the average, half a magnitude brighter at maximum than predicted by single-body theory and are about f shorter in duration and length. The breakup of meteors showing an abrupt beginning follows the relation 0v3=const (p is the air density, v the velocity). Using Verniani's (Smithsoman Astrophys. Obs. Special Re part 145, 1964) value, 1.0x10-19 zero mag g-1 cm-2 sec4, for the photographic luminous-efficiency Top, we find that the density of the average SuperSchmidt meteor is 0.26 g cnV2 a zero visual magnitude meteor with a velocity of 40 km/sec and zenith angle of 450 turns out to have a mass of 0.69 g. Among showers we find that the Geminids are four times denser than the average meteor, but crumble just as easily, while the Southern Taurids have normal densities, but do not fragment much; the Draconids are unique in their extraordinary fragility. A search for meteors of asteroidal origin has shown that only one of our 413 meteors possesses all the requisites to qualify as a member of this group. Publication: The Astronomical Journal Pub Date: 1965 DOI: 10.1086/109535 Bibcode: 1965AJ.....70Q.323J full text sources ADS |