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(meteorobs) Xi Draconid Orbit

Below are my preliminary orbit determinations of the Xi Draconid stream. Bob 
Lunsford and George Zay indicated the meteors seemed very fast, so a parabolic 
orbit (the fastest reasonable orbit) was computed from each of their orbits. 
They are as follows:

                         Zay              Lunsford
RA=                      274                280
DEC=                     +54                +53
Arg. of Peri.=           197.8              199.1
Ascending Node=           81.6               81.6
Inclination=              49.1               53.2
Perihelion distance=       0.991 AU           0.987
Eccentricity=              1.0                1.0

Just for the fun of it, I also computed an orbit for each radiant based on an 
assumed semi-major axis of 5 AU. Such a hypothetical orbit could make it a 
member of Jupiter's family of comets. 

                         Zay              Lunsford
RA=                      274                280
DEC=                     +54                +53
Arg. of Peri.=           199.0              200.5
Ascending Node=           81.6               81.6
Inclination=              46.0               50.1
Perihelion distance=       0.991 AU           0.987
Eccentricity=              0.802              0.803

As you can see, there is not a great difference between the angular elements of 
the orbital parameters. 

I then used these two orbits to serve as a guide in selecting the most likely 
candidates from the list I had obtained the other day. The orbits below are my 
preliminary selection. Now that I know what the orbit really looks like, I hope 
to put more refined search parameters into my database this weekend. 

              Probable Radio-Echo Meteors
  Date        RA     DEC    w      W      i     q      e
1962/06/18   277.4  +45.9  212.8  86.5  48.1  0.941  0.848
1962/06/18   285.7  +49.6  209.8  86.5  50.4  0.963  0.647
1962/06/21   284.7  +54.5  200.0  89.7  49.6  0.992  0.720
1963/06/04   275.4  +64.8  180.7  73.0  44.1  1.015  0.750
1964/06/01   280.1  +60.4  185.7  70.9  49.2  1.010  0.795
1965/06/01   269.1  +53.3  199.1  70.9  47.2  0.986  0.900
1969/06/02   275.9  +56.2  193.9  71.4  48.2  1.003  0.769
1969/06/03   283.8  +61.2  183.5  72.4  48.5  1.014  0.687
1969/06/03   285.6  +59.6  185.6  72.5  48.7  1.013  0.611

              Probable Photographic Meteors
  Date        RA     DEC    w      W      i     q      e
1954/06/02   269    +50    207    71    44    0.976  0.68
1953/06/04   271    +51    201    73    55    0.971  1.39
1954/06/11   279    +50    202    80    56    0.974  1.20

           Average Orbit (based on 12 meteors)
 06/01-21    278.1  +54.7  196.8  76.5  49.1  0.988  0.833

The average orbit certainly favors the Jupiter family of comets as its most 
likely origin. A more reliable orbit will be determined this weekend. The 
photographic meteors should be given a low weight, because of their low 
precision; however, their absence would not make a tremendous difference in the 
average orbit. 

Gary W. Kronk