Did a Supernova Shockwave Create Our Solar System? New Finding Says "Yes"
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August 04, 2012

Did a Supernova Shockwave Create Our Solar System? New Finding Says "Yes"

 

           CygnusLoop_hst

For decades it has been thought that a shock wave from a supernova explosion triggered the formation of our Solar System. According to this theory, the shock wave also injected material from the exploding star into a cloud of dust and gas, and the newly polluted cloud collapsed to form the Sun and its surrounding planets.

Traces of the supernova's pollution can be found in meteorites in the form of short-lived radioactive isotopes, or SLRIs. SLRIs—versions of elements with the same number of protons, but a different number of neutrons—found in primitive meteorites decay on time scales of millions of years and turn into different, so-called daughter, elements. A million years may sound like a long time, but it is actually considered short when compared to other radioactive isotopes studied by geochemists and cosmochemists, which have half-lives measured in billions of years.

New work from the Carnegie Institute's Alan Boss and Sandra Keiser provides the first fully three-dimensional (3-D) models for how this process could have happened. Their work will be published by The Astrophysical Journal Letters.* When scientists find the daughter elements distributed in telltale patterns in primitive meteorites, this means that the parent SLRIs had to be created just before the meteorites themselves were formed. This presents a timing problem, as the SLRIs must be formed in a supernova, injected into the presolar cloud, and trapped inside the meteoritic precursors, all in less than a million years.

The telltale patterns prove that the relevant daughter elements were not the ones that were injected. This is because the abundances of these daughters in different mineral phases in the meteorite are correlated with the abundances of a stable isotope of the parent element. Different elements have different chemical behaviors during the formation of these first solids, and the fact that the daughter elements correlate with the parent elements means that those daughters had to be derived from the decay of unstable parent elements after those solids were crystallized.

One of these SLRIs, iron-60, is only created in significant amounts by nuclear reactions in massive stars. The iron-60 must have come from a supernova, or from a giant star called an AGB star. Boss and Keiser's previous modeling showed that it was likely that a supernova triggered our Solar System's formation, as AGB star shocks are too thick to inject the iron-60 into the cloud. Supernova shocks are hundreds of times thinner, leading to more efficient injection.

Boss and Keiser have extended those models to 3-D, so they can see the shock wave striking the gas cloud, compressing it and forming a parabolic shock front that envelopes the cloud, creating finger-like indentations in the cloud's surface. The fingers inject the SLRI pollution from the supernova. Less than 0.1 million years later, the cloud collapses and forms the core of the protostar that became the Sun and its surrounding planets. The 3-D models show that only one or two fingers are likely to have caused the SLRI pollution found in primitive meteorites.

"The evidence leads us to believe that a supernova was indeed the culprit," said Boss. However, more detective work needs to be done: Boss and Keiser still need to find the combination of cloud and shock wave parameters that will line up perfectly with observations of exploding supernovae.

The image at the top of the page shows the Cygnus Loop supernova shockwave, created some 15,000 years ago a star in the constellation of Cygnus exploded. This picture shows a portion of a shockwave from this supernova explosion still expanding past nearby stars. The collision of this gaseous shockwave with a stationary gas cloud has heated the gas causing it to glow in a spectacular array of colors, known as the Cygnus Loop. This picture was taken with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope.

The Daily Galaxy via Carnegie Institute

Image Credit: NASA, HST, WFPC2, Jeff Hester

Comments

A simpler alternative model (paradigm shift) suggests that our central collapsing molecular cloud fragmented due to excess angular momentum, forming Saturn, Jupiter and a close binary pair. Then 'core collapse' perturbation lifted the orbits of Saturn and Jupiter at the expense of energy and angular momentum of the close binary pair, causing the binary pair to merge in a luminous red nova (LRN) at 4.567 Ga. Helium burning, r-process and alpha-process nucleosynthesis in the LRN created the short-lived radionuclides of the early solar system and enriched the sun in the stable isotopes, 12C, 14N and 16O, without resorting to a fortuitous local super nova.

A fortuitous local SN makes our solar system special, since most stars form without assistance, but apparently we still haven't learned the historical lesson about theories positing our vaunted place in the universe which have always yielded to paradigm shifts that prove otherwise.

Nice one! like it! Thanks!

@Snowball

Your post is reasonable, but I would posit that the fact that we're even actually discussing this at all makes our planet (at the very least) relatively special indeed.

@Taurus
You hit the nail right on the head. Some would say that we are a scourge to the Earth and are destroying the biosphere with our depletion of world resources; however compare our effect to the biosphere with the reproductive processes within a salmon that causes it to beat itself half to death running up a raging river to spawn and it becomes obvious why we are here; the difference is we are sentient and are becoming aware of the higher order that drives us to expand the boundaries of natural law that will in effect take evolution to the next step that would have not been possible without us.

The Solar System Formation.

Qoute: "A fortuitous local SN makes our solar system special, since most stars form without assistance, but apparently we still haven't learned the historical lesson about theories positing our vaunted place in the universe which have always yielded to paradigm shifts that prove otherwise", unqoute.

AD: "Stars doesn´t form without assistance" but via acticated dynamic forces of different kinds - and not via "gravity collapse".

Since our solar system clearly is an integrated orbiting part of the galactic formation, the formation of our solar system also must be considered as an integrated part of the galactic formation and not via a supposed Super Nova explosion.

The galactic formation takes place via several dynamic forces of atmospheric dynamics; thermodynamics; hydrodynamics; electrodynamics; magnetodynamics and nuclear dynamics - and it all goes in 3D spherical cell-like circuit of formation.


Lee,

'Density waves' in the spiral arms compress giant molecular clouds initiating spates of star formation, but once a critical density is achieved, gravity does the rest.


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