[meteorite-list] meteor trajectory inquiry

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Mon, 26 Jan 2009 13:43:52 -0700
Message-ID: <9730CC40AEE34B4B950E01A71D083F98_at_bellatrix>

The sightings in this case are unusual because they are so close to the
apparent event. As a rule, people don't see overhead meteors, so witness
reports tend to be richest 100 miles or more away, where you see the meteor
near the horizon (especially at times of the day, as in this case, where
most reports come from people in cars).

I don't know what the New England weather conditions were like at the time;
perhaps conditions outside the immediate area were not good for seeing into
Massachusetts. The reports suggest it was cloudy.

In any case, this pattern would suggest a fairly steep descent (which itself
makes it much less likely that any meteorites survived). Shallow descents
cover a lot of ground, so they are usually seen over wider areas- sometimes
over paths many hundreds of miles long.

Steep descents are associated with a rapid increase in pressure and an
earlier breakup of the parent, making it more likely that the debris will
burn up completely. The best scenario for meteorite production is a low
velocity (most likely to be seen in the early evening), and a relatively
shallow entry angle. That gives the meteoroid lots of time to slow down
without breaking into small pieces while the speed is still very high.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message -----
From: "teddy applebaum" <tiapplebaum at gmail.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Sunday, January 25, 2009 2:20 PM
Subject: [meteorite-list] meteor trajectory inquiry


> Hi list,
>
> I have been closely following the recent MA meteor sighting. I noticed
> that the numerous sightings for this particular bolide were seen only
> over a relatively small area. Does this point to the meteor having a
> more vertical trajectory in comparison to the atmosphere? In short do
> localized sightings tend to mean a steeper trajectory?
>
> Along this line of thought, do steeper trajectories mean an increased
> chance that material reached the ground since atmospheric ablation
> would occur for a shorter time? Any input would be appreciated - Teddy
Received on Mon 26 Jan 2009 03:43:52 PM PST