[meteorite-list] Supernova Shrapnel Found in Meteorite

[Greg Catterton]

Very cool info!
Here is a pic of my Orgueil
http://i27.photobucket.com/albums/c165/jedisdiamond/DSCF5360.jpg


Greg Catterton
www.wanderingstarmeteorites.com
IMCA member 4682
On Ebay: http://stores.shop.ebay.com/wanderingstarmeteorites
On Facebook: http://www.facebook.com/WanderingStarMeteorites


--- On Thu, 9/16/10, MEM <mstreman53 at yahoo.com> wrote:

> From: MEM <mstreman53 at yahoo.com>
> Subject: [meteorite-list] Supernova Shrapnel Found in Meteorite
> To: "metlist" <meteorite-list at meteoritecentral.com>
> Date: Thursday, September 16, 2010, 4:01 AM
> Yet another meteorite related news
> item.  Check your specimens for chromium 54 
> grains and see if you've hit the lottery for pre-pre-solar
> grains!  They will be 
> magnetic but at 100 nm not somehting you'll see with the
> eye alone.
> Elton
> 
> Supernova Shrapnel Found in Meteorite
> ScienceDaily (Sep. 14, 2010) — Scientists have identified
> the microscopic 
> shrapnel of a nearby star  that exploded just before
> or during the birth of the 
> solar system 4.5  billion years ago.
> 
> Faint traces of the supernova,  found in a meteorite,
> account for the mysterious 
> 
> variations in the  chemical fingerprint of chromium
> found from one planet and 
> meteorite to  another. University of Chicago
> cosmochemist Nicolas Dauphas and 
> eight co-authors report their finding in the late Sept. 10,
> 2010 issue of the 
> Astrophysical Journal.
> Scientists formerly believed that chromium 54 and other
> elements and  their 
> isotopic variations became evenly spread throughout the
> cloud of  gas and dust 
> that collapsed to form the solar system. "It was a
> very  well-mixed soup," said 
> Bradley Meyer, a professor of astronomy and astrophysics at
> Clemson University  
> who was not a co-author of the study. "But it looks like
> some of the  
> ingredients got in there and didn't get completely
> homogenized, and  that's a 
> pretty interesting result."
> Scientists have known for four decades that a supernova
> probably  occurred 
> approximately 4.5 billion years ago, possibly triggering
> the  birth of the sun. 
> Their evidence: traces of aluminum 26 and iron 60,
> two  short-lived isotopes 
> found in meteorites but not on Earth.
> These isotopes could have come from a type II supernova,
> caused by  the 
> core-collapse of a massive star. "It seems likely that at
> least one  massive 
> star contributed material to the solar system or what was
> going  to become the 
> solar system shortly before its birth," Meyer said.
> Researchers have already extracted many type II supernova
> grains from 
> meteorites, but never from a type IA supernova.  The
> latter type involves the 
> explosion of a small but extremely dense  white-dwarf
> star in a binary system, 
> one in which two stars orbit each  other. It should
> now be possible to determine 
> 
> which type of supernova contributed the chromium 54 to the
> Orgueil meteorite.
> "The test will be to measure calcium 48," Dauphas said.
> "You can make  it in 
> very large quantities in type Ia, but it's very difficult
> to  produce in type 
> II." So if the grains are highly enriched in calcium
> 48,  they no doubt came 
> from a type Ia supernova.
> Cosmochemists have sought the carrier of chromium 54 for
> the last 20  years but 
> only recently have instrumentation advances made it
> possible  to find it. 
> Dauphas's own quest began in 2002, when he began the 
> painstaking meteorite 
> sample-preparation process for the analysis he was 
> finally able to complete 
> only last year.
> Dauphas and his associates spent three weeks searching for
> chromium 54-enriched 
> nanoparticles with an ion probe at the California Institute
> of Technology. "Time 
> 
> is very precious on those instruments and getting three
> weeks of instrument time 
> 
> is not that easy," he said.
> The researchers found a hint of an excess of the
> chromium-54 isotope  in their 
> first session, but as luck would have it, they had to
> search  1,500 microscopic 
> grains of the Orgueil and Murchison meteorites before 
> finding just one with 
> definitely high levels.
> The grain measured less than 100 nanometers in diameter --
> 1,000  times smaller 
> than the diameter of a human hair. "This is smaller
> than  all the other kinds of 
> 
> presolar grains that have been documented before, except
> for nanodiamonds that 
> have been found here at the University of Chicago," Dauphas
> said.
> The findings suggest that a supernova sprayed a mass of
> finely  grained 
> particles into the cloud of gas and dust that gave birth to
> the  solar system 
> 4.5 billion years ago. Dynamical processes in the
> early  solar system then 
> sorted these grains by size. These size-sorting 
> processes led the grains to 
> become disproportionally incorporated into  the
> meteorites and planets newly 
> forming around the sun.
> "It's remarkable that you can look at an isotope like
> chromium 54 and  
> potentially find out a whole lot about what happened in the
> very first  period 
> of the solar system's formation," Meyer said.
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