Smithsonian Contributions to Astrophysics VOLUME 7 PROCEEDINGS OF THE SYMPOSIUM ON THE ASTRONOMY AND PHYSICS OF METEORS Held at SMITHSONIAN ASTROPHYSICAL OBSERVATORY Cambridge, Massachusetts August 28-September 1, 1961 Sponsored by Smithsonian Astrophysical Observatory, Cambridge, Mass. and Geophysical Research Directorate, Air Force Cambridge Research Laboratories, Office of Aerospace Research, U.S. Air Force. Coordinated by Wentworth Institute, Boston, Mass. SMITHSONIAN INSTITUTION Washington, D.C. 1963 Publications of the Astrophysical Observatory This series, Smithsonian Contributions to Astrophysics, was inaugurated in 1956 to provide a proper communication for the results of research con- ducted at the Astrophysical Observatory of the Smithsonian Institution. Its purpose is the "increase and diffusion of knowledge" in the field of astro- physics, with particular emphasis on problems of the sun, the earth, and the solar system. Its pages are open to a limited number of papers by other investigators with whom we have common interests. Another series is Annals of the Astrophysical Observatory. It was started in 1900 by the Observatory's first director, Samuel P. Langley, and has been published about every 10 years since that date. These quarto volumes, some of which are still available, record the history of the Observatory's researches and activities. Many technical papers and volumes emanating from the Astrophysical Observatory have appeared in the Smithsonian Miscellaneous Collections Among these are Smithsonian Physical Tables, Smithsonian Meteorological Tables, and World Weather Records. Additional information concerning these publications may be secured from the Editorial and Publications Division, Smithsonian Institution, Washington, D.C. FBED L. WHIPPLE, Director, Astrophysical Observatory, Smithsonian Institution. Cambridge, Mass. For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. - Price $2.75 Contents Session 1 Welcoming address: Col. Ernest A. Pinson, USAF 3 Limitations of radar techniques for the study of meteors: J. S. Greenhow 5 The initial radius of ionized meteor trails: B. L. Kashcheyev and V. N. Lebedinets 19 The initial diameter of meteor trails: G. S. Hawkins 23 The relation between visual magnitudes of meteors and the durations of radar echoes: B. A. Lindblad 27 Radio-echo measurements of meteor mass distributions: A.A.Weiss . 41 A preliminary report on radar meteor counts: P. M. Millman and B. A. Mclntosh 45 The Harvard radio meteor project: G. S. Hawkins 53 Meteor rates observed by radio-echo techniques during the IQY-IGC period: B. L. Kashcheyev and K. V. Kostylyov 63 The orbits of meteor streams determined by radio-echo techniques: B. L. Kashcheyev, V. N. Lebedinets, and M. F. Lagutin . 67 Session 2 The distribution of small interplanetary dust particles in the vicinity of Earth: C. W. McOacken and W. M. Alexander 71 Micrometeorite measurements from Midas II (Satellite 1960 f 1): R. K. Soberman and L. Delia Lucca 85 Micrometeorite collection from a recoverable sounding rocket. I: R. K. Soberman, C. L. Hemenway, T. G. Ryan, S. A. Chrest, J. Frissora, and E. F. Fullam 89 Micrometeorite collection from a recoverable sounding rocket. II: C. L. Hemenway, R. K. Soberman, E. F. Fullam, J. J. Balsamo, J. Cole, D. Hallgren, P. Yedinak, A. Goodman, and G. Hoff 93 Micrometeorite collection from a recoverable sounding rocket. Ill: R. K. Soberman and C. L. Hemenway 99 Rocket and satellite studies of meteoric dust: T. N. Nazarova . 105 Cosmic dust showers by direct measurements: M. Dubin, W. M. Alexander, and O. E. Berg 109 Discussion: 115 Session 3 A general survey of meteor spectra: P. M. Millman 119 Meteor spectra with high dispersion: Zd. Ceplecha and J. Rajchl . 129 A short note on meteor spectra with low dispersion: J. Rajchl ... 155 Spectrographic observations of meteors in U.S.S.R. in 1967-1960: E. N. Kramer, K. A. Liubarsky, and V. I. Ivanikov .... 157 in Page Diffusion effects observed in the wake spectrum of a Geminid meteor: I. Halliday 161 On the frequency of occurrence of the auroral green line (5577A) in Perseid spectra: J. A. Russell 171 Session 4 Negative ions and luminosity in meteor trains: T. R. Kaiser .... 175 Luminosity from large meteoric bodies: H. J. Allen and K. K. Yoshikawa 181 Preliminary notes on some results of photographic multiple meteorite fall of PHbram: Zd. Ceplecha 195 Results from an artificial iron meteoroid at 10 km/sec: R. E. McCrosky and R. K. Soberman 199 Luminous efficiency of iron and stone asteroidal meteors: A. F. Cook, L. G. Jacchia, and R. E. McCrosky 209 Meteor ionization and the mass of meteoroids: D. M. Lazarus and G.S.Hawkins 221 Statistical verification of the physical theory of meteors: B. J. Levin and S. V. Majeva 229 On the color index of meteors: J. Davis 233 Image-orthicon photographs of meteors: J. Spalding, G. Colter, C. L. Hemenway, J. A. Cole, and J. F. Dugan 237 Meteoritic erosion in space: F. L. Whipple 239 The absence of magnetic micropulsations of meteor origin: C. Ellyett and G. B. Gillion 249 Session 5 The density distribution of telescopic meteors around the earth's orbit: L. Kresak and M. Kresakova 253 Atmospheric trajectories of telescopic meteors: L. Kohoutek and J. Grygar 259 Statistics of meteor streams: R. B. Southworth and G. S. Hawkins . 261 Orbital elements of photographic meteors: P. Babadjanov 287 On the structure of the 5-Aquarid meteor stream: A. K. Terentjeva . 293 Masses of Comet Giacobini^Zinner and the Draconid meteor stream: Y. V. Yevdokimov 297 Dynamical evolution of the Perseids and Orionids: R. B. South- worth 299 A note on the cometary nature of the Tungus meteorites: V. Fessenkov 305 A short note on the origin and age of the Quadrantids: S. E. Hamid and Mary N. Youssef 309 Abstracts of other papers 313 IV PROCEEDINGS OF THE SYMPOSIUM ON THE ASTRONOMY AND PHYSICS OF METEORS Welcoming Address By Col. Ernest A. Pinson, USAF * It is my great pleasure to extend a welcome dous potentialities for research in this field. to this distinguished assembly on behalf of the A good example of new opportunities for con- Geophysics Kesearch Directorate of the Air trolled experimentation is the recent artificial Force Cambridge Research Laboratories. We meteor experiment, which will be discussed in are pleased to be associated with the Smithso- detail during the meeting. nian Astrophysical Observatory in cosponsoring Meteor physics experiments have now become this symposium, and with the Wentworth global in nature, requiring ever greater coopera- Institute as coordinating agency. Our long- tion among world scientists. It is encouraging standing interests in astrophysics are empha- to note that international cooperation in this sized this week in this symposium and in field is flourishing; information is being exchang- another international astrophysical symposium ed on a personal basis and appears in the open on the Solar Corona, which we are sponsoring literature as soon as it has been reduced and at Cloudcroft, N. Mex., during this same week. analyzed. Our fervent hope is that such The latter is Symposium No. 16 of the Inter- cooperation will continue and even increase. national Astronomical Union. In this regard, I am happy to offer the use of The U.S. Air Force is interested in studies any space available on our research vehicles to that can be applied to the solution of specific worthy meteor experiments that may be problems of the space environment. However, forthcoming. we fully recognize that theoretical and experi- The extent and degree of international mental studies that appear, on the surface, cooperation that may soon be required is only to increase knowledge of our universe illustrated by our consideration of the possi- invariably lead to useful applications and solu- bility of using a ground-based network of tions of specific problems. photographic and radio observations of natural As most of you know, the last international meteoric phenomena for determining high- meteor physics symposium was held at Jodrell altitude winds and densities. Bank in 1954. A brief examination of the Briefly, the 1954 symposium spoke in terms proceedings of that symposium reveals the of local, ground-based meteor studies, and of tremendous growth in meteor measurement and international cooperation. Soon, the meteor observation techniques that has taken place physicist will be unrestricted—within our during the past few years. This meeting is solar system—as to mode and place of observa- the first opportunity for people specializing in tion. International cooperation is therefore meteor physics to gather at an international even more essential. symposium to discuss measurements made May I again extend the greetings of the Air above the earth's atmosphere. The advent of Force Cambridge Research Laboratories and rocket and satellite vehicles has opened tremen- our best wishes for a fruitful and provocative 1 Vice commander, Air Force Cambridge Research Laboratories. exchange in this important area of research. 3 Limitations of Radar Techniques for the Study of Meteors By J. S. Greenhowl Radar techniques are widely used for the The scattering theories study of the physics and astronomy of meteors, Linear electron densities less than 1012 cm'1.— and observations of echoes from the ionized When the linear electron density a is less than trails have also been used as a tool for the approximately 1012 cm"1, the scattering equa- study of the upper atmosphere. Various scat- tion derived by Lovell and