Supernova shrapnel found in meteorite

Sep 09, 2010
This false-color image of Kepler’s supernova remnant combines data taken in X-rays (Chandra X-ray Observatory), visible light (Hubble Space Telescope) and infrared radiation (Spitzer Space Telescope). University of Chicago cosmochemist Nicolas Dauphas and his colleagues have been analyzing meteorites for the microscopic remnants of a supernova that exploded approximately 4.5 billion years ago. (NASA/ESA/R. Sankrit and W. Blair, Johns Hopkins)

( -- 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 , account for the mysterious variations in the of 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 .

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 . The latter type involves the explosion of a small but extremely dense white-dwarf star in a , 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 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.

Explore further: Thermonuclear supernova ejects our galaxy's fastest star (w/ video)

More information: “Neutron-rich chromium isotope anomalies in supernova nanoparticles,” Sept. 10, 2010, Astrophysical Journal, by Nicolas Dauphas, Laurent Remusat, James Chen, Mathieu Roskosz, Dimitri Papanastassiou, Julien Stodolna, Yunbin Guan, Chi Ma, and John Eiler.

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User comments : 11

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1.7 / 5 (11) Sep 09, 2010
Yes, indeed!

Iron meteorites themselves are shrapnel ejected directly from the core of the Sun when it exploded five (5) billion years (Gyr) ago to give birth to the Solar System.

See: "Elemental and isotopic inhomogeneities in noble gases: The case for local synthesis of the chemical elements" [Trans. Missouri Acad. Sci. 9, 104 122 (1975)]; "Strange xenon, extinct superheavy elements and the solar neutrino puzzle" [Science 195, 208-209 (1977]; "Isotopes of tellurium, xenon and krypton in the Allende meteorite retain record of nucleosynthesis" [Nature 277, 615-620 (1979)]; "Strange Molybdenum in iron meteorites" [Qi-Lu, Doctoral Dissertation, The University of Tokyo (1991) and Nature 415 (2002) 881].

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
4.3 / 5 (11) Sep 09, 2010
The sun exploded? I presume your talking about a different sun that the one I see in the sky most days (some days its cloudy).

Surely you can quote more recent source for this claim than the 1970's before modern theories had developed that explain the 'puzzles' cosmologists had 40 years ago. The dissertation you quote from 1991 doesn't propose that the sun exploded 5 bya.
1.9 / 5 (9) Sep 09, 2010
The sun exploded? I presume your talking about a different sun that the one I see in the sky most days (some days its cloudy).

The Sun is a recycled star. It formed on the core of the precursor star. Here are a couple of more recent paper:

"The Sun is a plasma diffuser that sorts atoms by mass",
Physics of Atomic Nuclei 69 (2006) 1847-1856

"Earth's Heat Source - The Sun",
Energy & Environment 30 (2009) 131-144

With kind regards,
Oliver K. Manuel
4.4 / 5 (7) Sep 09, 2010
"The Sun is a recycled star. It formed on the core of the precursor star."

On what core did the precursor star form?
4.1 / 5 (9) Sep 09, 2010
Mr. Manuel

Why is this behavior not observed in the stellar population?

What leads you to believe that the observed nucliogenesis was expelled by Sol, and not a supernova?

Your model has a lack of observable phenomena, doesn't it. We observe supernova. We observe supernovae remnants. We observe supernova shock waves imparting kinetic energy upon clouds of gas. We observe clouds of gas coalescing. We observe knots of coalesced gas start fusion. We observed proto-planetary disks. We observe planetary disks. We observe planets.

Where are your observations?
1.6 / 5 (7) Sep 10, 2010
On what core did the precursor star form?

We do not know.

The precursor star probably had a neutron core, just like the Sun.

From the precursor to the precursor? We do not know.

From the observations, it seems that nuclear matter is now mostly dissociating rather than fusing together, going in exactly the opposite direction to the popular Big Bang model:

"Big Bang" => Hydrogen (H)

H => He => C => . . . . =>Fe => Neutron Star

Instead: Neutron Star => n => H => Interstellar space.

Shootist, please see experimental data in the above papers.

With kind regards,
Oliver K. Manuel

1 / 5 (4) Sep 10, 2010
How long does supernova remnants hang around in the place where the explosion took place?
Should we not be seeing this kind of evidence of said type Ia explosion still hanging around the solar system?
3.4 / 5 (5) Sep 10, 2010
Iron meteorites themselves are shrapnel ejected directly from the core of the Sun
This is highly improbable - I'd expect instead, that vaporized iron plasma condensed well outside of supernova.
5 / 5 (3) Sep 10, 2010
Dr. Manuel,

We now have witnessed and can calculate the exact actions that will occur when a degenerate star comes in contact with non-degenerate matter.

Large scale energy transfer and consistently observed "re-nova" would be the result if our Sun was a neutron star. We would not be having this conversation. I'm sorry, but your hypothesis is disproved. It is time to let it go and move forward to bigger and better things.
1 / 5 (4) Sep 10, 2010
How long does supernova remnants hang around in the place where the explosion took place?

Good question. Some answers were posted as "Related Articles" on my website in late 2006:

"Scientists discover comets come from our Sun", Nature, 18 Dec 2006
"Onion-skin layers survive SN explosion!" CalTech, 26 Oct 2006
"Element layers remain in supernova debris," NASA, 26 Oct 2006
"Supernova was stunningly close",, 24 Oct 2006

Other observations confirmed what the measurements of meteorites first revealed:

1972: Isotopes were unmixed when SN debris formed meteorites [1].
1975: Major light elements were linked with specific isotopes of heavy elements [2].

1. "Xenon in carbonaceous chondrites", Nature Phys. Sci. 240, 99-101 (1972).

2. "Elemental and isotopic inhomogeneities in noble gases: The case for local synthesis of the chemical elements", Trans. Missouri Acad. Sci. 9, 104 122 (1975).

With kind regards,
Oliver K. Manuel
not rated yet Sep 14, 2010
It is great to find concrete evidence for long standing theories.

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