[meteorite-list] Orionoid micrometeorites

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Mon, 22 Oct 2012 09:51:53 -0600
Message-ID: <50856B99.6090908_at_alumni.caltech.edu>

I doubt you were seeing micrometeorites, and almost certainly not
Orionid micrometeorites. While there is iron in Halley's dust trail, it
remains a trace constituent. Orionid micrometeorites should be
silicates, not iron particles.

You don't state the size of particles observed, but typical
micrometeorites are in the 1-10 um diameter range. These particles
require months or even years to settle to the ground. Even huge
micrometeorites- 100 um diameter- would require about 100 hours to reach
the ground, so you wouldn't see them until days after the shower peak.

I've recovered particles very much like what you describe (using a
custom built micrometeorite collection device), and have subjected the
most interesting to examination under an electron microscope (with
dispersion analysis). All proved to be nothing more than industrial
smokestack debris- and I'm high in the Rockies where the air has a very
low particulate count. Where you live, I doubt you'd ever pick out
micrometeorites from the vast array of industrial pollutants.

Chris

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

On 10/22/2012 9:07 AM, b1dunovant at aol.com wrote:
> Hello Listees. I hope everyone enjoyed the weekend.
>
> I live in the Chicago suburbs and was not able to view the Orionoid
> meteor shower due to overcast skys and horrible light polution from the
> city. Knowing this would be the case, Two weeks ago while cleaning the
> gutters on the house I rinsed the entire roof off several times so that
> the amount of shingle material left in the gutter was less and less each
> rinse, until finally there was hardly anything coming off. Yesterday I
> affixed a fine screen to the end of my drain shoots and collected all
> the material that I was rinsing off. I soaked all the material in
> anhydrous alcohol for several hours and dried then dried in silica gel.
> What I had was a mix of different shigle materials, tiny twigs and
> hopefully something of interest.
>
> I use a rare earth magnet to seperate the material into a pile of
> magnetic and a pile of non-magnetic materials. The magnetic material was
> them put in a petri dish and was sorted throught under high
> magnification for hours removing small magnetic materials in the rough
> shingle grit. After working all day doing this seperation i was left
> with stuff that left me with my jaw dropped.
>
> What i was looking at were aerodynamiclly shaped black metalic pieces,
> some perfectly round, some pancake shaped, some bars, a couple buttons
> with rollover all around such as you would see in some indochinites, and
> even severl tear-dropped pieces with unbroke tails. Under even higher
> magnification you could see surface details and even multple skins on
> some of the tear drops and bb's. Along with them there were also bb's
> that looked slightly oxidized and were an orange color I assume were
> missed during the initial roof rinses, however the the mass majority
> were shiny black and had very fine sufrface detail under magnification.
>
> Is there a chance these are condensents of vaporized material from the
> Orionoid shower? If not why such the high concentrations of unoxidized
> aeroforms so dilicate I doubt would still have such perfect tails after
> my rigourous rinsing ahead of the meteor shower.
>
>
> Email me off list if your interested in pictures of what I've described
> above. I would love to hear some feedback from the community! I should
> have some pictures up for the masses to view shortly.
>
> Regards,
>
> Brandon D.
> IMCA# 9312
Received on Mon 22 Oct 2012 11:51:53 AM PDT