Reexamination of Allende meteorite reveals isotopic evidence of supernova

Oct 14, 2013 by Bob Yirka report
A 520g individual of the Allende meteorite shower. Credit: H. Raab / Wikipedia.

(Phys.org) —A combined team of researchers from Lawrence Livermore National Laboratory and Arizona State University has found isotopic evidence of a supernova inside of a meteorite that fell to Earth in 1969. In their paper published in Proceedings of the National Academy of Science, the team describes how isotopes found in the Allende meteorite differ from those found on Earth or on the moon, suggesting they came directly from a supernova rather than from a debris field that followed.

Scientists agree that our solar system formed approximately four and a half billion years ago—how exactly it happened, however, is still a of debate. Most agree that it was likely the result of one or more stars exploding, because the heavy matter that makes up our planet is only known to form in stars, or when they explode as a . Research has even led to a theory describing how three types of isotopes come about: p-, s- and r-processes, from which all matter heavier than nickel is made. In this new effort, the researchers found isotopes inside the Allende that conform to the r-process; this they contend, suggests that the isotopic material very likely came about directly when a supernova exploded. The rest of the meteorite (the outer shell) likely came about as debris from the explosion followed sometime later. This discovery has added new details to theories about the way our solar system came to exist.

One theory suggests that a single supernova explosion led to the creation of our sun and later the planets as debris from the explosions entered the system. Another suggests that our sun could have been created by more than one supernova, all of which would have likely contributed, via debris, to the matter that coalesced into planets. The material in the Allende meteorite helps refine such theories by narrowing the window of its injection into our system to a relatively small time frame—perhaps as small as 20 to 50 thousand years.

Clumps inside the meteorite, known as inclusions, are believed to represent some of the oldest material in the solar system and offer the best evidence possible of what was happening as our was being created.

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More information: Evidence for supernova injection into the solar nebula and the decoupling of r-process nucleosynthesis, PNAS, Published online before print October 7, 2013, DOI: 10.1073/pnas.1307759110

Abstract
The isotopic composition of our Solar System reflects the blending of materials derived from numerous past nucleosynthetic events, each characterized by a distinct isotopic signature. We show that the isotopic compositions of elements spanning a large mass range in the earliest formed solids in our Solar System, calcium–aluminum-rich inclusions (CAIs), are uniform, and yet distinct from the average Solar System composition. Relative to younger objects in the Solar System, CAIs contain positive r-process anomalies in isotopes A < 140 and negative r-process anomalies in isotopes A > 140. This fundamental difference in the isotopic character of CAIs around mass 140 necessitates (i) the existence of multiple sources for r-process nucleosynthesis and (ii) the injection of supernova material into a reservoir untapped by CAIs. A scenario of late supernova injection into the protoplanetary disk is consistent with formation of our Solar System in an active star-forming region of the galaxy.

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Shootist
1.3 / 5 (12) Oct 14, 2013
Calling Doctor Oliver Manuel.
Torbjorn_Larsson_OM
5 / 5 (2) Oct 14, 2013
Well, the most predictive and least finetuned theory I've seen has been with two consecutive mass injections. First from a 1st generation of supernovas from large stars in a mostly pristine molecular cloud. Then a 2nd gen large stars that injected the final isotopes and decided the size of the solar system because of the shell formation of clouds around large stars.

This seems much the same except they are adamant on that the 2nd gen is a supernova instead, and adding some (hopefully unnecessary) timetable finetuning. Not that several generations of supernovas couldn't happen in molecular clouds.

"Most agree that it was likely the result of one or more stars exploding, because the heavy matter that makes up our planet is only known to form in stars,".

Independent processes, as the heavy elements formed earlier, but our specific deviance from Milky Way normal composition (from spectral measurements) is predicted from 1-2 supernovas related to system formation.
Pressure2
1 / 5 (12) Oct 14, 2013
Calling Doctor Oliver Manuel.


Oliver is most likely right about the supernova origin of our solar system.
GSwift7
2 / 5 (3) Oct 14, 2013
as with many things in astronomy, the sheer vastness of space will eventually tell us the answer. By observing thousands of systems we will notice patterns regarding system characteristics such as size and composition versus system formation evvironments. Then we will classify solar systems by type, just like we do stars.

As for the above article, isn't it a bit premature to make assumptions based on only one sample? How do we know the origin of the Allende meteorite?

I think it is likely that a relatively young and actively star-forming galaxy like the Milky Way has a lot of mixing going on, especially in the dense regions like the arms and the core. This might make the average star kinda like a mutt; composed of such a mixed bag of ingredients that it's hard to trace its ancestry with certainty. We might be made up of a combination of stars and gas that came from other combinations of stars and gas, etc, etc.
Kron
1 / 5 (12) Oct 14, 2013
the heavy matter that makes up our planet is only known to form in stars, or when they explode as a supernova.

There are no "knowns" in science!
revision:
the heavy matter that makes up our planet is suspected to have formed in stars, or when they explode as a supernova.

Correction:
Heavy elements are created in labs regularly by elemental bombardment with deuterium.
jsdarkdestruction
1.8 / 5 (5) Oct 15, 2013
Calling Doctor Oliver Manuel.

lmao, I thought of that too. you KNOW he's out there going on and on about how this proves the sun is a neutron star that went supernova because of neutron repulsion . I bet he nearly had a heart attack he got so excited.
GSwift7
5 / 5 (2) Oct 15, 2013
Correction:
Heavy elements are created in labs regularly by elemental bombardment with deuterium


If you only want a few atoms, then that's fine. Try starting with billions of tons of carbon and iron and produce billions of tons of heavy elements from them. The energy to do that does not exist on the Earth or even all the planets of the solar system combined. Even the collision of massive objects does not fuse atoms, and that's about the most energetic thing we know of that isn't a stellar event.

So, when the article says 'is only known to form in stars', they are correct because there's not enough energy to create the observed abundance of heavy elements in any other 'known' place.
Kron
1 / 5 (13) Oct 15, 2013
It is highly probable that the observed stellar energy output is the result of nuclear fusion, but highly probable does not equate to certain. There is a difference between an absolute (or known, or true) and probable. I'm bothered by bad reporting which conveys scientific results as truth in a way that religions do. I fear that science will become the new religion. Science at its core is based on tenets and premises, not facts and truths.

So no GSwift7, when the author says: "heavy matter" is only known to form in stars, it is not correct. Fusion is suspected to occur within stars (it is highly probable mind you, but not known). Furthermore, I've pointed out that the statement is not only falsely worded by presenting certainty where there is none, but that the statement is factually wrong. "Heavy matter" is also produced in laboratories (ie NOT only in stars).
Fleetfoot
5 / 5 (3) Oct 15, 2013
So no GSwift7, when the author says: "heavy matter" is only known to form in stars, it is not correct.


The statement is accurate. There may be other methods of creating heavier elements but if there are, they are not known to us.

If it had said "'heavy matter' is known only to form in stars" then your point would be valid.

Of course you can nitpick about lab production but the assumption is that we are talking about natural processes.
PhotonX
4 / 5 (1) Oct 15, 2013
There are no "knowns" in science!
How about this? Science knows it will never detect the element plutonium in stellar spectra.
.
Correction:
Heavy elements are created in labs regularly by elemental bombardment with deuterium.
For the same reason as above, and as others point out, artificially creating enough plutonium to be visible in a spectroscope is probably beyond the capability of even a Type II civilization, and we haven't found many of those around thus far. I guess you could argue that we can't observe the spectrum of a Dyson sphere, but that's more nit-picking until we see even one of those.
GSwift7
5 / 5 (1) Oct 16, 2013
it is highly probable mind you, but not known). Furthermore, I've pointed out that the statement is not only falsely worded by presenting certainty where there is none


If you're going to take certainty to an unreasonable level, then I will counter with the equally unreasonable assertion that your statement falsely presents itself as being certain that the aforementioned statement was falsely presenting itself as certain. In fact, I'll take it a step farther and suggest that you cannot even prove that either of us made a statement, or that you exist at all, and therefore it is impossible to decide if you are right or not.

Really, come on dude. You've gotta allow reasonable assumptions. I'm willing to assume that you and I exist and I think we can agree to define the Univese as 'real', for example. lol, that was funny though.