[meteorite-list] Calculating a meteorite orbit

From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Fri Sep 24 13:59:38 2004
Message-ID: <AF564D2B9D91D411B9FE00508BF1C86904EE607A_at_US-Torrance.mail.saic.com>

Hi Dieter,

I resisted replying to Pierre-Marie's question for the very reason that
there is no "turn-key" solution to determination of the pre-Earth-encounter
orbit based on visual observations, video, photographs, and/or recovered
meteorite coordinates. Every case is unique since the type and quality
of data vary in every fall.

You were extraordinarily fortunate with Neuschwanstein because the quality
and quantity of your camera data were excellent. (I wish we had such a
network in the U.S. -- there are a few scattered all-sky cameras in
northern California, but nothing yet in southern California or Nevada
where the chances are better for meteorite recovery.) But even with
good camera records, I know how much work it was for you to reconstruct
the 3-D trajectory and compute an impact corridor. You need an atmospheric
model, an ablation model, and code for "flying" the meteoroid down to
the ground -- compensating for upper atmospheric winds as necessary.
Few people appreciate the complexity of the problem until they actually
try to do it. I spent hundreds of hours doing it for the June 3rd
Washington State bolide [paper pending].

The reverse problem of flying the atmospheric trajectory backwards in
order to compute the solar orbit is almost as difficult. However, it
can be a valuable clue if you haven't found any meteorites yet, since
the orbit (primarily the semi-major axis and eccentricity) may tell you
the probable composition of the meteoroid. (This turned out to be
especially true in the case of the June 3rd bolide!)

Best wishes,
Rob

-----Original Message-----
From: meteorite-list-bounces_at_meteoritecentral.com
[mailto:meteorite-list-bounces_at_meteoritecentral.com]On Behalf Of Dieter
Heinlein
Sent: Thursday, September 23, 2004 11:02 PM
To: pierre.pele_at_voila.fr
Cc: Meteorite List
Subject: Re: [meteorite-list] Calculating a meteorite orbit


Hello Pierre-Marie,

some years ago I have written a booklet on the Pribram, Lost City or
Innisfree falls,
describing the reduction procedure how to calculate the meteoroid orbit from
the
fireball trajectory. It's written in German, but anyhow you will be mostly
interested
in the formulas I guess. This booklet is still available from us on request.

Btw, this procedure was used also in the recent case of the successful
recovery of
the Neuschwanstein meteorites. But the process is time consuming and not
easy to
explain! Don't expect to get an Excel spreadsheet which gives you the result
in a
few minutes. It's really hard work....

Best regards

Dieter
Received on Fri 24 Sep 2004 01:56:15 PM PDT