[meteorite-list] Updated Lorton trajectory

[Rob Matson]

Hi All,

I finally received a good second image of the Lorton bolide smoke
trail taken immediately after the fall (and before upper atmospheric
winds distorted it). More importantly, the two images I have were
taken from sufficiently different vantage points that a good 3D
solution could be computed. (My early, somewhat hurried "first-cut"
at the trajectory was based on only a single image, and a cobbling
together of 50+ witness reports.) That first solution wasn't bad
as far as the flight direction (NNE -> SSW); however, as steep as
I made the entry angle, I didn't make it steep enough.

The Lorton meteoroid entered at a surprisingly steep angle -- about
15 degrees from vertical! If upper atmospheric winds had been
light, this would have made for a very tight strewnfield. But
those winds were anything but light at the time of the fall. For
instance, at 11-km altitude, the jet stream was over 90 knots!
Even down at 5-km altitude, the wind was over 40 knots.

So here are my new impact predictions as a function of mass.
The distance and bearing columns are in miles and degrees,
respectively, relative to the impact coordinates of the 308-gram
mass:

Mass   Longitude Latitude Distance Bearing
-----  --------- -------- -------- -------
 3 g    -77.1383  38.7130   4.05    77.9
10 g    -77.1635  38.7104   2.68    75.5
30 g    -77.1804  38.7077   1.75    74.0
100 g   -77.1976  38.7043   0.80    71.8
300 g   -77.2116  38.7007   -0-      N/A
 1 kg   -77.2282  38.6965   0.94    252.1
 3 kg   -77.2415  38.6923   1.72    250.2
10 kg   -77.2560  38.6874   2.57    249.0

As before, these coordinates (when you connect the dots) trace
out a curve of the estimated strewn field centerline. Unfortunately,
the lightest (and presumably more numerous) fragments would have
been windblown onto Ft. Belvoir. But there is still some room ENE
of the doctor's office that is not on military land, and plenty
of real estate in the "heavy direction" (WSW) if you're feeling
lucky.  --Rob