[meteorite-list] Fwd: First cut at wind-shifted, predicted impact coordinates

[Paul Harris]

Hi Mike,

Yes, Rob does amazing work and finds an incredible number of meteorites 
too.  So many in fact that I often wondered how he was able to transport 
them all home at the end of a hunt.  Then one day while Jim and I were 
out hunting I discovered the answer...

http://www.meteorite.com/rob.jpg

Jim and I are looking forward to seeing everyone soon at Tucson!
http://www.meteorite-times.com/tucson/

Paul




Mike Hankey wrote:
> Hi,
>
> Meteor wizard Rob Matson has taken a first crack at estimating a
> strewnfield for the Lorton Meteorite.
>
> I have plotted the points in Google Earth. You can see some maps and
> download the KMZ file here:
>
> http://www.mikesastrophotos.com/astro-photos/lorton-meteorite-estimated-strewnfield-version-1/
>
> Its looking like the Fort Belvoir Golf Course could be prime hunting grounds.
>
> Rob is the only person I know of who is qualified to do this type of
> work and willing to share it with the meteorite community. Rob's work
> has been instrumental in numerous meteorite discoveries and we all owe
> him a debt of gratitude.
>
> Thanks Rob!
>
> Mike
>
>
>
>
> Hi Guys,
>
> I've done some serious data-gathering and number-crunching
> today to come up with a hunting corridor for you. Here are
> my current best assumptions based on witness observations,
> images of the dust cloud, the impact location, and upper
> atmospheric radiosonde data for the balloon launched from
> Sterling, VA, about an hour after the fall:
>
> Entry angle: ~55-60 degrees from horizontal (i.e. steep)
> Flight direction:  Azimuth +191 (11 degrees west of south)
> Average wind velocity from 5-16 km altitude:  70 knots
> Average wind direction from 5-16 km altitude:  Az 90 (east)
>
> Using an example break-up altitude of 25 km at an initial
> velocity of 15 km/sec, the rotation of the strewn field
> relative to flight direction ends up being 40-50 deg clockwise,
> which is quite significant. Here are where masses of various
> sizes end up, both in Lat/Long and distance/bearing from the
> 308 g find:
>
>  Mass    Longitude  Latitude  Dist (mi) Bearing
> -------  ---------  --------  --------- -------
>   3 g    -77.12929  38.73888     5.2      59.3
>   5 g    -77.14419  38.73268     4.3      58.7
>  15 g    -77.16179  38.72688     3.2      56.0
>  40 g    -77.18079  38.71908     2.1      52.6
> 120 g    -77.19569  38.71088     1.1      50.6
> (308 g)  -77.21159  38.70068     -0-      N/A
> 1150 g   -77.22609  38.69048     1.1     228.0
> 3750 g   -77.24249  38.67848     2.3     227.4
>
> The reason the masses aren't round numbers is that my program
> includes ablation, so while the simulated stones started off
> with nice round numbers like 100 g and 1 kg at altitude, the
> ablated masses are a fraction of the original.
>
> So where are these locations? The 120-gram mass ends up near
> Rhondda Drive, a couple hundred meters NW of Richmond Highway
> and Telegraph Rd. The 40-gram mass ends up on the north end
> of Ft. Belvoir. The simulated 15-grammer ends up on the Ft.
> Belvoir golf course. But 5-gram stones would be off the base
> to its north, north of John J. Kingman Rd. And 3-gram stones
> end up in the southwest corner of Huntley Meadows Park.
>
> Going in the other direction (heavier masses), the ~1.1 kilo
> simulated mass above ends up very close to I-95, a little
> west of Morris Ginsberg & Co.  And the largest mass I ran
> crosses over to the other side of I-95 on Landfill Drive. ;-)
>
> If you connect all these dots, you should find quite a bit
> of searchable real estate.  My advice is on a map to draw a
> 45 degree angle southwest of the doctor's office for heavier
> stones, and a ~55-degree angle NE of the 308-g find for the
> lighter stuff (that's 55-degrees clockwise from north).
>
> I'll continue to search for better observations that can
> yield a more accurate entry angle.  We really need a good
> observer who had a side view of the event and can tell us
> what the slope was like relative to the horizon.  --Rob
> ______________________________________________
> Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html
> Meteorite-list mailing list
> Meteorite-list at meteoritecentral.com
> http://six.pairlist.net/mailman/listinfo/meteorite-list
>
>
>