METEORS — WHIPPLE 



251 



Probably a comet ejects meteoric material continuously, at least 

 every revolution near the time of perihelion passage. It is an inter- 

 esting commentary on these conclusions that the Taurid meteor stream 

 had been first identified as a hyperbolic meteor stream by earlier 

 investigators. 



Our measures of the detailed meteoric photographic processes give 

 us added information concerning the nature of the bodies that pro- 

 duce the ordinary visual or photographic meteors. Jacchia (1955) 

 showed that the irregular bursts in the light curves of some meteors 

 were accompanied by a shortening of the lifetimes. He concluded 

 that bursts in these meteors represent a rapid disintegration or frag- 

 mentation of the meteoric body at irregular intervals along their 

 trails. 



ORBIT OF 

 ENCKE'S COMET 



Figure 8. — The orbits of Encke's comet, and of three meteors of the associated northern 

 Taurid shower that struck the earth's atmosphere on the dates shown. 



Measurements of the slowing down of meteors, or atmospheric 

 resistance, lead to the determination, for each meteor, of the quantity, 

 surface-frontal-area divided by the mass. A knowledge of the at- 

 mospheric density, now provided by rocket techniques, enables us 

 to determine the quantity m^p^ where m is the mass of the meteoric 

 body and p m its density. If we knew the amount of light that should 

 be produced by a given meteoric mass at a given velocity we could 

 immediately calculate, from the light curve and the velocity meas- 

 urements, the initial mass of the body. Unfortunately, the theoret- 

 ical determination of this so-called luminous efficiency is not yet 



