[meteorite-list] Fragments of Daylight Meteor Found in California

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 25 Apr 2012 13:17:19 -0700 (PDT)
Message-ID: <201204252017.q3PKHJVx018445_at_zagami.jpl.nasa.gov>

http://cosmicdiary.org/fmarchis/2012/04/25/daylight_meteor_incalifornia/

Fragments of the daylight meteor found in California
Franck Marchis
Cosmic Diary Network
April 25, 2012

It all started on Sunday Morning April 22 at 7:51am PDT, when several
people located in the Northern California and Reno areas reported seeing
a bright fireball visible in daylight.

The American Meteor Society compiled a list of 121 visual observations
on their web site
<http://www.amsmeteors.org/fireball2/public.php?start_date=2012-04-01&end_date=2012-04-31&state=CA&event_id=&submit=Find+Reports>,
an impressive number for a full sunlight meteor. Several observers in
Nevada also mentioned having heard a sonic boom, implying that the
meteoroid was large enough to penetrate the lower part of Earth???s
atmosphere.

Bill Cooke of the Meteoroid Environments Office at NASA's Marshall
Space Flight Center in Huntsville, Ala., estimates the object was about
3-4 m, weighed in at around 70 metric tons and at the time of
disintegration released energy equivalent to a 4-kiloton explosion.
(reported in NASA-JPL press release
<http://www.jpl.nasa.gov/news/news.cfm?release=2012-114>).

Lisa Warren snapped three quick photos of a meteor streaking across the
sky above Reno on Sunday morning, April 22. The meteor created a sonic
boom heard over hundreds of miles from the Reno-Tahoe area to Southern
California.

This event interested my office neighbor at the SETI Institute,
Peter Jenniskens, an expert in meteor showers who also retrieved the
fragments of 2008TC3
<http://en.wikipedia.org/wiki/2008_TC3> in Sudan in 2008. He pointed out
that the size of the Californian meteor is very similar to 2008TC3,
hence fragments should have reached the surface. Getting fresh fragments
of meteoroids, called *meteorites*, is key for astronomers to understand
the composition of those remnants of the formation of the solar system.
Fresh fragments are unaltered by the Earth's weather and erosion
processes, so they are pristine samples which can be used to detect
organic materials for instance.

On Tuesday several scientists from the Bay Area met at NASA Ames to
discuss a strategy for a search campaign. An examination of the radar
data map
<http://radarmeteorites.wordpress.com/2012/04/23/coloma-ca-22-apr-2012-1452-utc/>
by Marc Fries revealed that dozens of fragments from 100g to 1 kg
range may have reached the surface in an area NW of Placerville, in the
Gold country.

Yesterday, Tuesday April 24, Peter Jenniskens and Mike Koop drove to the
site of the radar map. The possible presence of fragments was already
spreading quickly and an email was posted on the meteorite-list mailing
list announcing that Robert Ward found the first piece at 11am.

New California meteorite found!
Sean T. Murray
Tue, 24 Apr 2012 13:33:22 -0700
It is an honor to announce that, at 11:00 am local, Robert Ward was the
first to recover a stone from the April 22, 2012, California fireball --
which was evidently generated by a large, carbonaceous CM mass. Robert is
now responsible for the initial recovery of two-out-of-three-ever
California

A second fragment was discovered shortly later by Peter Jenniskens
himself. It appears to be a CM Chondrite meteorite, one of the rarer
types of meteorites, rich in a mix of complex organic compounds like
amino-acids. They graciously sent me this picture taken at the time of
the discovery.

Unfortunately a storm is reaching California and the rain may alter the
remaining fragments. If you are not too far and feel like looking for
meteorites, you should definitely check out the area for meteorites.
They are easily discernible thanks to their dark color.

Another plea for help, if you have access to security camera footage
taken on Sunday morning, it may be useful to check them to see if the
fireball was visible. Astronomers could use them to pin down the site of
the fall, maximizing the hunt for fragments.

Clear skies & good hunting,

Franck M.

Edit at 11am:

>From Marc Fries: A third stone was found by a gent from Sacramento. He
went up there and walked around on the roads, and found it on a gravel
road.
Received on Wed 25 Apr 2012 04:17:19 PM PDT