Exploding star missing from formation of solar system

Dec 17, 2012 by Chelsea Leu
Scientists in the University of Chicago’s Origins Laboratory are about to publish the latest in a series of papers about the origin of the solar system. Infant stars glow reddish-pink in this infrared image of the Serpens star-forming region, captured by NASA’s Spitzer Space Telescope. Four-and-a half billion years ago, the sun may have looked much like one of the baby stars deeply embedded in the cosmic cloud of gas and dust that collapsed to create it. Credit: NASA/JPL-Caltech/L. Cieza (University of Texas at Austin)

(Phys.org)—A new study published by University of Chicago researchers challenges the notion that the force of an exploding star prompted the formation of the solar system.

In this study, published online last month in , authors Haolan Tang and Nicolas Dauphas found the radioactive isotope iron 60—the telltale sign of an —low in abundance and well mixed in solar system material. As cosmochemists, they look for remnants of in meteorites to help determine the conditions under which the solar system formed.

Some remnants are radioactive isotopes: unstable, energetic atoms that decay over time. Scientists in the past decade have found high amounts of the iron 60 in early solar system materials. "If you have iron 60 in high abundance in the solar system, that's a 'smoking gun'—evidence for the presence of a supernova," said Dauphas, professor in .

Iron 60 can only originate from a supernova, so scientists have tried to explain this apparent abundance by suggesting that a supernova occurred nearby, spreading the isotope through the explosion.

But Tang and Dauphas' results were different from previous work: They discovered that levels of iron 60 were uniform and low in material. They arrived at these conclusions by testing . To measure iron 60's abundance, they looked at the same materials that previous researchers had worked on, but used a different, more precise approach that yielded evidence of very low iron 60.

Previous methods kept the meteorite samples intact and did not remove impurities completely, which may have led to greater errors in measurement. Tang and Dauphas' approach, however, required that they "digest" their meteorite samples into solution before measurement, which allowed them to thoroughly remove the impurities.

This process ultimately produced results with much smaller errors. "Haolan has dedicated five years of very hard work to reach these conclusions, so we did not make those claims lightly. We've been extremely careful to reach a point where we're ready to go public on those measurements," Dauphas said.

To address whether iron 60 was widely distributed, Tang and Dauphas looked at another isotope of iron, iron 58. Supernovae produce both isotopes by the same processes, so they were able to trace the distribution of iron 60 by measuring the distribution of iron 58.

"The two isotopes act like inseparable twins: Once we knew where iron 58 was, we knew iron 60 couldn't be very far away," Dauphas explained.

They found little variation of iron 58 in their measurements of various samples, which confirmed their conclusion that iron 60 was uniformly distributed. To account for their unprecedented findings, Tang and Dauphas suggest that the low levels of iron 60 probably came from the long-term accumulation of iron 60 in the interstellar medium from the ashes of countless stars past, instead of a nearby cataclysmic event like a supernova.

If this is true, Dauphas said, there is then "no need to invoke any nearby star to make iron 60." However, it is more difficult to account for the high abundance of aluminum 26, which implies the presence of a nearby star.

Instead of explaining this abundance by supernova, Tang and Dauphas propose that a massive star (perhaps more than 20 times the mass of the sun) sheds its gaseous outer layers through winds, spreading aluminum 26 and contaminating the material that would eventually form the solar system, while 60 remained locked inside the massive star's interior. If the solar system formed from this material, this alternate scenario would account for the abundances of both isotopes.

"In the future, this study must be considered when people build their story about origin and formation," Tang said.

Explore further: Fermi finds a 'transformer' pulsar

More information: "Abundance distribution, and origin of 60Fe in the solar protoplanetary disk," by Haolan Tang and Nicolas Dauphas, Earth and Planetary Science Letters, December 2012.

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Lurker2358
1.4 / 5 (9) Dec 17, 2012
Conservation laws make it nearly impossible for a Supernova of one star to produce terrestrial planets in another, because the velocity of the explosion cannot be stopped by the gravity of a M class star, except in the case of head-on collisions. Most of the material from a Supernova has two or three times the galactic escape velocity.

I've been trying to tell people this forever, and they don't listen.

It's more likely that a star MIGHT produce planets from failed supernovas of it's own core, than by picking up debris from another supernova.

To account for their unprecedented findings, Tang and Dauphas suggest that the low levels of iron 60 probably came from the long-term accumulation of iron 60 in the interstellar medium from the ashes of countless stars past, instead of a nearby cataclysmic event like a supernova.


Still can't rule out star worship, eh?

Early astrologers in many cultures worshiped their star gods. It seems astronomers still can't let go of their idols.
GSwift7
4.4 / 5 (14) Dec 17, 2012
Lurker

Conservation laws make it nearly impossible for a Supernova of one star to produce terrestrial planets in another, because the velocity of the explosion cannot be stopped by the gravity of a M class star


Try reading the following wiki page as a starting point regarding the basics of supernova remnants:

http://en.wikiped..._remnant

We have plenty of supernova remnants to observe, so there is little doubt about what happens to the material over time. The ejected material eventually encounters other material in interstellar space and loses its momentum. You aren't talking about meteors here. The ejected material is individual atoms, so it doesn't take much to slow them down. We estimate about 30k years is all it takes for supernova ejecta to lose momentum and become part of the interstellar medium.
Lurker2358
1.5 / 5 (8) Dec 17, 2012
Not only have the crab nebula's remnants not slowed down their expansion in the past thousand years, they are actually known to be accelerating their expansion.

Excluding nebulas, the amount of interstellar and intergalactic media from here to the edge of the light horizon is equivalent to about 4 centimeters of water.

The amount of matter blown out of the crab nebula dwarfs that, in terms of mass per unit area, even stretched across it's entire surface area. It would not even be significantly slowed down by that.

Sure, some of it will have head-on collisions with planets and stars, eventually, by chance some if it may eventually hit Earth and even our planets and Saggitarius A, but that's a minor dusting, nearly insignificant at those ranges. Most of the matter is going to keep expanding right into inter-galactic space, as there is nowhere near enough gravity, even in the entire galaxy, to stop it.

A 1kg paricle cloud has same momenta as a 1kg ball of iron of the same velocity.
rubberman
3 / 5 (4) Dec 17, 2012
Hey Lurk, the Em fields in the ISM are the force that eventually slows down this type of Nebular expansion (the same way the EM radiation from the progenitor star accelerate this particular expansion). The solar system formation theory is that the leading wave of material collides with a molecular cloud of star forming material and the ensuing reactions initiate the star forming process. You are correct that gravity would have little effect on this, EM is the primary influence when it comes to this. The journey is much too long for any of the ejecta except for the GR's to actually leave the galaxy. I don't know if it is actually a theory or just my opinion, but once you have one star, the energy from it's ignition propegates through the cloud and causes the process to repeat.
Torbjorn_Larsson_OM
5 / 5 (1) Dec 17, 2012
Perhaps. It is actually easier to predict the 60Fe and 26Al results from a sequential process in the nascent molecular cloud, where the 60Fe is produced by rapid, ~ 10 Ma, 1st gen supernovas and the 26Al is produced by slower, ~ 100 Ma, 2nd gen massive stars akin to proposed here. [ http://www.aanda....emid=129 ]

But I guess this works too, if these new results will win out.

@Lurker: "Conservation laws make it nearly impossible for a Supernova of one star to produce terrestrial planets in another, because the velocity of the explosion cannot be stopped by the gravity of a M class star, except in the case of head-on collisions."

I have absolutely no idea what you are envisioning. Protoplanetary nebulas develops in molecular clouds, see above, and that is how the solar system originated too.

The subsequent planetary formation process is too rapid to be influenced by supernova.
Torbjorn_Larsson_OM
5 / 5 (3) Dec 17, 2012
The 2nd gen massive star 26Al seeder is important because of what the linked paper describes. Such a spherical shell it blows up, creating ~ 600 stars together with the Sun, predicts the outer characteristics of the solar system: the Kuiper belt outer dimensions, some of its specific objects, and the Oort cloud size.

These are exactly the missing characteristics that the Nice model with the 5th giant modification _can't_ predict! (The inner terrestrials, as well as their ice line & carbon line, are of course best predicted by specific disk aggregation models.)

So any which way, we now have good handles on how the whole system arose. That is clearly some awesome astronomical archaeology!
unknownorgin
not rated yet Dec 18, 2012
I find it odd that gold is not studied in these samples because as far as I know it only forms in supernovas and it would be easy to detect by several methods such as mass spectragraph or atomic absorbtion ect.
dav_daddy
1 / 5 (1) Dec 18, 2012
I find it odd that gold is not studied in these samples because as far as I know it only forms in supernovas and it would be easy to detect by several methods such as mass spectragraph or atomic absorbtion ect.


IIRC the amount of gold produced is proportionate to the mass of the star. You would need a truly massive star to go Nova for their to be a chance of detecting gold if even then.

That is why Gold is so rare as opposed to say iron which all stars cook up and is also responsible their going Nova in the end.