[meteorite-list] Observed lunar meteorite impacts hit 100

From: lebofsky at lpl.arizona.edu <lebofsky_at_meteoritecentral.com>
Date: Wed, 21 May 2008 19:09:28 -0700 (MST)
Message-ID: <53779.71.226.60.25.1211422168.squirrel_at_timber.lpl.arizona.edu>

Hi Chris:

If I remember correctly (probably an old estimate) about 10% of the NEOs
are thought to have a cometary origin.

Also, many asteroids do contain volatiles (20% or more by weight), just
not as much as your "typical" comet.

Larry

On Wed, May 21, 2008 4:14 pm, Chris Peterson wrote:
> Hi Mark-
>
>
> There have been a few meteorites that some have speculated might be
> related to showers. But most likely, none are.
>
> Nobody even really knows if asteroids and comets are all that different,
> other than comets containing volatiles. Recently, it has been suggested
> that a few objects we consider asteroids may in fact be burned out comets.
> And nobody really knows if the rocky material in comets is
> actually fragile at all.
>
> The best argument against shower-origin meteorites is velocity: most
> shower members are simply traveling too fast to avoid burning up high in
> the atmosphere. The few showers that have slow components also, for the
> most part, are low activity- barely above the sporadic background.
>
> The way I'd start a serious investigation of this would be to compare
> fall dates and times with low velocity showers. Where you have a match, it
> might be worth trying to determine if witness reports of the fireball
> suggest a direction that is at least reasonably consistent with the shower
> radiant.
>
> Chris
>
>
> *****************************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
>
>
> ----- Original Message -----
> From: "Mark Crawford" <mark at meteorites.cc>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Wednesday, May 21, 2008 4:29 PM
> Subject: Re: [meteorite-list] Observed lunar meteorite impacts hit 100
>
>
>
>> This got me thinking... some of the lunar impacts are being attributed
>> to well-known meteor showers.
>>
>> Are there any good candidates for (earthly) meteorites which may be
>> part of such showers, and therefore potentially once part of the presumed
>> parent body? I guess candidate criteria would be time of year and (at
>> least rough visual) triangulation back to the radiant.
>>
>> Or as many/most showers are associated with comets rather than
>> asteroids, is the material perhaps much more fragile and therefore less
>> likely to reach the earth's surface?
>>
>> Mark
>>
>
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Received on Wed 21 May 2008 10:09:28 PM PDT