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(meteorobs) 1967 IAU symposium on Meteor Physics and Dynamics-(long)



---------------------------------- Forwarded ----------------------------------
From: Joseph Assmus at PACE-POST
Date: 12/10/96 9:30PM
To: lewkaren@tiacdot net at @UCSD
Subject: 1967 IAU symposium on Meteor Physics and Dynamics-(long)
-------------------------------------------------------------------------------
At 2:05 PM 1996.12.04, Joseph_Assmus@PACE-POST.ucsddot edu typed:
> I have also found two great books on meteor science in the University library
> (Lovell and the text of the IAU 1968? meeting on Physics and Dynamics of
> Meteors).

>>Hi, Joe. BTW, if you can see your way clear to sending me a photocopy of the
>>IAU Also, maybe you can summarize the interesting stuff you found to the
>>list later!

>>Lew Gramer 77 Magoun Ave.   Medford, MA 02155
>>PS: Let me know any copying and postage costs involved. Thanks!


     Hey, man, This is So Cal .. Land of Perpetual Cleariness... We see clear
  each day...  could xerox it here, but...

     The IAU Symposium No. 33 was held at Tatranska Lomnica, Czechoslovakia,
  4-9 Sept 1967. The text ia an edited collection of 50 scientific papers
  (from 9 "sessions") totaling 525 (beautiful) high-gloss pages...  It's a
  heavy text, both in weight and content... Well, Lew.. Here goes it.. A
  summary , if you will, Hope this will be useful...
 =============================================================================

|-----------------------------------------------------------------------------
| Formal title of book is: PHYSICS AND DYNAMICS OF METEORS.
| Editor: Lubor Kresak, Astro Inst of Slovak Acad Sci(AISA), Bratislava, Czech
|         Peter M. Millman, Natl Research Council, Ottawa, Canada
| Publisher: D. Reidel Publishing Co, Dordrecht-Holland, 1968
|_____________________________________________________________________________

 There's seems to be loose topical threads between the session-grouped
  papers. the first 2 seesions are heavy in radio meteor echo methodology,
  reporting and a study of relevant factors affecting data collection...

    Here's the INTRO (Session 2, Paper 7) on Meteor Spectra presented by
  Z. Ceplecha, Czech, AISA)..

    "Meteor luminosity is frequently used for the computation of meteor mass.
  This procedure is a rough approximation only if the spectral distribution
  of the energy and its changes during meteor flight are not known.  A
  good-quality photograph of a meteor spectrum includes much more
  information on the meteor phenomenon than any other method can provide.
  There is of course a stronger limitation by meteor brightness than for
  direct meteor photography.  Detailed spectral analysis is available for
  meteors 4 or 5 magnitudes brighter than for those photographed directly.
  This could be the reason meteor spectroscopy is not applied to a desirable
  extent for the study of meteor phenomnenon".

  I think I understand that!?  Anyway, that was 1967. What about now?
  ---------------------------------------------------------------------------
     Here are mouth-watering titles of the 7 papers presented in Session 7:
  (my favorite thus far!):

  - 1. Structure and evolution of meteor streams, L Kresak
  - 2. Discrimination of stream and sporadic meteors, RB Southworth
  - 3. On the grouping of meteors in meteor streams, V Porubcan
  - 3. Investigaion of minor-meteor streams, AK Terenteva
  - 4. On the width of the Geminid shower at faint radio magnitude, Z Plavcova
  - 5. Radar observations of the Leonid in 1965-66, Z Plavcova
  - 6. Observations of the Leonid meteor shower in Nov '66 in USSR, V Bronsten
  ----------------------------------------------------------------------------
     About that 3rd paper above:  At first, I thought 'grouping' implied
  making 'shower association'. NOT!.. this is important enough I ought to just
  type it out, but allow me to abrev when poss... (INTRO from the 3rd paper
  listed above)....

      "It has been repeatingly suggested, on the basis of visual amd radar
  obs, that meteors often appear in pairs, or in larger groups, within short
  time intervals.  They usually have some similar characteristic (mag, path)
  so they easily attract the obs'ers attention. this phenom could be a result
  of chance and only an analysis of its freq can give answer whether there is
  any A PRIORI reason for it.  The poss reality of this grouping has been
  studied by some authors.  However, those obs contained data on meteors
  ONLY brighter than mag +8, and did NOT yield umbiguously accepatable
  evidence for the existence of real pairs in this range and said nothin
  abouot the region of very small meteors."

    ... the paper goes on to BRIEFLY present radar data from 32,600 echos,
  7400 of which were obtained at Ondrejov (Czech?), Lm=+7, in the period of
  the Geminids 1959 and 1961.  25,200 echos are from Dusanbe (Czech?),
  Lm=+13.5, containing Lyrids, Perseids, Aurigids, Orionids and one maximum
  from 10/28/66...

    ... a nice BRIEF analysis using rules of Poisson distributions and
  interval and time series analyses... author actually answers this question
  purely matematically using 4 different methods...

  ANSWER:

   "The assumption of the grouping of meteors that were obtained in some
  previous investigations was NOT confirmed here"


  ...IS THIS THE FINAL WORD ON 'GROUPING'?
 ----------------------------------------------------------------------------
  ... THen we get to Session 8 and some more interesting Leonid papers ... a
  recent HOT!HOT! topic, eh?... a paper On the modeling of Leonid stream
  perturbations using 100 years of data!! (1866-1966)... Also, Fred Whipple
  writes "Origins of meteoric material (survey paper)"... and "Collisional
  Models of Asteroids and their Debris" .. (Geminids, anyone?)
 -----------------------------------------------------------------------------
  ... There ARE 2 papers discussing a very recent MeteorsObs thread
          'On the radiant distribution of sporadic meteors'
        'A note on the sporadic meteor radiant distribution'
 -----------------------------------------------------------------------------
   Favorite technical paper:  The relation between orbits and the physical
                              characteristics of meteors.

   ... They talk about diffs between asteroidal and cometary meteors and
  mention the Draconids alot.
  ---------------------------------------------------------------------------
   Favorite paper (fun reading):  Fireball radiants of the 1st-15th centuries

   ... It even sounds fun...  data on 1220 fireballs from 153 showers, seven
  of which belong to great showers. Out of the remaining 146 radiants of minor
  showers, 80 radiants are more certain than the remainder...  By studying
  these fireball radiants, they arrive at several conclusions.  The authors
  state  "The radiants were deduced from observation on dates recorded in
  short intervals from short years to several decades".  Seems they relied
  much on the works of E Biot, who published a work under the Institut
  National de France in 1848... studing this, author were enabled to use
  material that had recorded in the "well-known" 13th century ENCYCLOPEDIA of
  Ma Touan-lin.   In the end, they had data on 1500 fireballs covering 24
  centuries ...from this, they distilled their 1220 obs records for further
  processing ... anyway the stated conclusions:


    1. It appears the Perseid stream began to cross earth orbit in 830 A.D.
    2. In the delta-Aquarids, the N branch was active, while there is no
       evidence that the S brance existed before 900 years ago.
       (My comment... Gary K. talks about this very "ancient" stream)
    3. The Virginids, Librids, Scorpionids, Sagittarids, Aurigis were quite
       appreciable and their studies furnish much intersting data.
    4. Particularly active were the TAU. N and S branches observed over 1000
       years back.  The STA were about 1/2 active as NTA (at presrent the
       situation is reversed).
    5. Very active were the Cygnids (July-August), which presented at the time
       a very compact shower, now disrupted into a series of minor showers
       with radiants spread over a wide area of the celestial sphere.
    6. Of definitive interest is the radiant of the great meteor shower
       observed in 1037 (Aug 21 - Julian date, Sept 9 Greg calander, 1950.0),
       [alpha = 324 deg, delta = +1 deg (1950.0)]
  ---------------------------------------------------------------------------
    Well, enough summarizing ...


    Let me know if anyone is interested in receving 2pg FAX of ALL 50 paper
  titles.  Most of the papers are fairly short.  If a particular one sounds
  good, Ill FAX it whole paper... cheaper for me to FAX, rather than send via
  mail... some of the better titles have been given above.  Ive got the text
  chked out until Feb 1, 1997.

    Hope this has been informative.


    Regards and clear skies to all,

    Joseph Assmus
    Office of Sleep and Circadian Studies, UCSD
    San Diego, CA
    jassmus@ucsddot edu