(meteorobs) Whitmire, SC likely fall location

Matson, Robert D. ROBERT.D.MATSON at saic.com
Wed Feb 15 12:54:13 EST 2012


Hi All,

I found the confirming radar hits (from two radars) yesterday
afternoon -- I can send the .KMZ files to anyone that is
interested. They are definitely associated with the fall.
The reflectivity, velocity and spectral returns all have
the "candystriping" that Marc Fries and I have come to
associate with past confirmed meteorite falls.

The location is not as bad as it could be. Yes, lots of
forest, but also many cleared areas due to the nearby
town of Whitmire, SC.  --Rob

-----Original Message-----
From: meteorobs-bounces at meteorobs.org on behalf of Esko Lyytinen
Sent: Wed 2/15/2012 2:57 AM
To: Meteor science and meteor observing
Subject: Re: (meteorobs) [meteorite-list] GA SC Bolide seems have produced a large rock
 

I made a one station analysis of the Lawndale camera video.

The camera was calibrated with eight found stars. And a number of frames 
were manually measured.
A direct fit to the timed directions gives the apparent entry direction 
approximately. In this a reasonable looking deceleration was taken into 
account.
Some level "scaling" can be got by means of an assumed beginning height, 
consistent with the resulting velocity, with a few iterations.
I get it arriving form az-direction around 315 or 325 . The entry 
velocity seems to be about 13 km/s having then he beginning height at 
around 80 or 85 km.

The reulting landing site from this model is very close to Jake's 
southers radar "group". I tried a further velocity (and connected 
beginnig height fit) and with the entry velocity of 13.4 km/s (in this 
model arriving from direction 319) with resulting beginning height of 
about 85 km. Now there is an almost exact hit! The end height in this is 
26 km. Camera calibration at low elevation angles may be not so good 
affecting some uncertainty to this.
Also a resonable rough dark flight was modeled. In this the landing is 
13.8 km before the sea-level crossing of the direct track.
Then the prediction from this would be a few kilometer to the West of 
the radar hits.

Wind effects are not taken into account and may well affect this.
Just now the server in Wyoming tell

"Sorry, the server is too busy to process your request.
Please try again later."

when trying to get the atmospheric sounding data.

I am practically confident that these "southern" radar hits are from 
this. It would be good to know the exact time of the radar hits.
In my opinion the northern hit it less probabaly from this.

No reliable end deceleration is derived from this. And from only one 
station data, this may not be got quite reilably. Ablation model would 
give a reasonable end mass for this velocity and end height of around 5 
kg (if OC). But if this was strongly fragmented in early flight, as may 
well have happened, considering the bright flashing, this mass value may 
rather suit to the biggest mass(es) and the total end mass may be bigger.

The fall-time to the radar height would be telling on the masses of these.

Regards,
Esko


> Here is my analysis of this meteor:
>
> http://3dradar.wordpress.com/2012/02/15/sc-2132012-at-642-utc/
>
> I think there is a chance there could be meteorites from this event. I
> think it is highly misleading to say it "produced a large meteorite"
> when nothing has been found yet...
>
> I think the radar hits probably need further scrutiny (Marc Fries, Rob
> Matson?) but it seems from what I see, this meteor deserves a bit more
> attention?
>
> - Jake
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