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 <[email protected]> wrote: > From: MEM <[email protected]> > Subject: [meteorite-list] Supernova Shrapnel Found in Meteorite > To: "metlist" <[email protected]> > 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. > ______________________________________________ > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
