Sol System — the "Kiss of Life"

[Widdekind]

(1) According to the National Geographic Channel documentary Naked Science -- Birth of the Solar System (TV), scientists have detected Iron-60 isotopes in meteorites. Iron-60 comes exclusively from Supernovae events, and has a relatively short Half-Life. Therefore, Iron-60 typically decays before traveling very far from its source.

 

Thus, this strongly suggests, that the nascent Solar System was w/in about 20 light-years of some Supernovae event.

 

 

(2) About 4.6 billion years ago, when our star system was born, it was comparatively metal-rich, for its time & place:

In the

Galaxy

as a whole, the

Star Formation Rate

peaked

about 8 to 10 billion years ago

, and has been declining ever since.

Today

, the

Metallicity

in the solar neighborhood is increasing by about 8% every

billion years

...

 

The

Thin Disk

is the Sun's home. The

Metallicity

of its gas declines w/ distance from the

Galactic Center

. At the Sun's location, about 8.5 kiloparsecs (

28,000 light-years

) out, it is decreasing at 17% per kiloparsec...

 

The

Sun itself is about 40% richer in metal than other stars formed

at the same time

[~

4.6 billion years ago

] & location in the

[Thin] Disk

. This increased metal content may have given life on Earth a head start

*

.

Moreover, Iron-Peak compounds — presumably including Iron-60 — are produced mainly by Type I Supernovae events, "most of which result from the detonation of a White Dwarf star"**.

*

Guillermo Gonzalez, Donald Brownlee, & Peter D. Ward.

Refuges for Life in a Hostile Universe

.

Printed in: [scientific American]

Majestic Universe

, pg. 8.

**

ibid

., pp. 8-9.

 

 

CONCLUSION: The nascent Solar System was within about 20 light-years of an exploding White Dwarf, which enriched the Proto-Solar Cloud with copious quantities of Iron-Peak compounds. And, since stellar Metallicities strongly correlate w/ Planetary Formation probabilities, this exploding White Dwarf helped beget our Planetary System, orbiting our Sun.

Edited August 29, 2009 by Widdekind

[Airbrush]

I thought a white dwarf is what is left AFTER a supernova. How can a white dwarf explode if it is so dense, about one ton per cc?

[Widdekind]

I think it requires accretion from a companion, until it exceeds the Chandrasekhar Mass Limit of roughly [math]1.4 M_{\odot}[/math].

[Arch2008]

Did you perhaps mean nickel-60 or iron-56? The following does not show an iron-60 isotope to be the product of nucleosynthesis.

http://www.tufts.edu/as/wright_center/cosmic_evolution/docs/text/text_stel_6.html

[Widdekind]

Thanks for the link, but I think I accurately quoted the program:

 

http://www.msnbc.msn.com/id/5023748/

 

Theorists have speculated since the 1970s that the sun might have formed in a dense region of starbirth. The latest evidence for a chaotic birthplace comes from meteorites that have landed on Earth after orbiting the sun for billions of years.

 

The rocks contain chemical patterns that can only be created by the radioactive decay of an isotope of iron called iron-60... The iron-60 must have been present in the early solar system but has since decayed into telltale nickel-60 in the meteorites.

 

"There is no way that you can form iron-60 other than in a massive, evolved star," Hester told Space.com. And that implies the sun must have been near a massive star when it formed about 4.6 billion years ago.

 

The iron-60 discovery was made last year by Arizona State researchers Shogo Tachibana and Gary Huss. The finding supports other evidence for the sun having formed near a massive star, said Alan Boss, a planet-formation theorist at the Carnegie Institution of Washington, "with the advantage that iron-60 can only be created in a supernova and so there is no room for debate about where it formed."

[Airbrush]

"The Sun itself is about 40% richer in metal than other stars formed at the same time [~4.6 billion years ago] & location in the [Thin] Disk."

 

Do you mean richer in metal than stars in our area? If so how can that be, for a supernova to enrich the Earth with more metals than our neighboring stars?

[Moontanman]

"The Sun itself is about 40% richer in metal than other stars formed at the same time [~4.6 billion years ago] & location in the [Thin] Disk."

 

Do you mean richer in metal than stars in our area? If so how can that be, for a supernova to enrich the Earth with more metals than our neighboring stars?

 

The Sun moves around the core of the galaxy in it's own orbit, the local neighbor stars are not the same stars that were neighbor stars when the Sun was formed. The Sun moves around and up and down through the galactic disc and there is no way to know for sure where the sun formed or if any other stars formed at the same time or where they might be.

[Widdekind]

"The Sun itself is about 40% richer in metal than other stars formed at the same time [~4.6 billion years ago] & location in the [Thin] Disk."

 

Do you mean richer in metal than stars in our area? If so how can that be, for a supernova to enrich the Earth with more metals than our neighboring stars?

 

The Type II SN, ~4.6 GYA, which triggered the formation of our star system, surely triggered the formation of other star systems, "nearby", in the "neighborhood" of the Sun at that time. In principal, it is possible to (perhaps partially) reconstruct the Sun's "stellar sibko" — to wit, that group of stars w/ which the Sun first formed. For, the Sun's "stellar siblings" would all have highly similar properties — the same age (~4.6 GY), the same "metallcity mix", and similar galactic orbital parameters (radius ~8.5 kpc, period ~220 MY). Indeed, such "stellar families" could be tracked much as Astronomers today track "asteroid families" in our Solar System's Main Asteroid Belt (eg. the Baptistina group, responsible for the impactor(s) that killed off the Dinosaurs ~65 MYA).

http://www.astronomyforum.net/planetary-forums/84613-how-find-suns-sibling-stars-exo-planets.html

However, such "stellar sibkos" — to wit, Open Clusters — typically disperse over hundreds of millions of years. Today, after roughly 4.6 GY, the Sun's "stellar sibko" is surely smeared out over a vast stretch of the Galactic disk. So, as previously pointed out above, our nearby neighboring star systems today are not necessarily our "stellar siblings", from roughly 4.6 GYA.

 

But, apparently, after restricting attention to all known stars, in our Galactic disk, that have similar Galactic orbital parameters, and similar stellar ages, the Sun seems to be about 40% richer in metals, as compared to that limited sub-sample of stars. That gives us a "window to the past", and allows us to conclude, that, ~4.6 GYA, the Sun was a comparatively metal-rich star (surely along w/ all its "stellar siblings").

[D H]

The original hyopthesis, sans all the silly colored text:

The nascent Solar System was within about 20 light-years of an exploding White Dwarf, which enriched the Proto-Solar Cloud with copious quantities of Iron-Peak compounds. And, since stellar Metallicities strongly correlate w/ Planetary Formation probabilities, this exploding White Dwarf helped beget our Planetary System, orbiting our Sun

 

A change of gears occurred midstream, and now the change is official:

The Type II SN, ~4.6 GYA, which triggered the formation of our star system, surely triggered the formation of other star systems, "nearby", in the "neighborhood" of the Sun at that time.

 

OK, which is it, Widdekind, that "triggered" the formation of our solar system, a type I or type II supernova? You are contradicting yourself.

 

Moved to pseudoscience and speculations.

[Moontanman]

Has anyone done a study of stars to see if any match the metal "print" of our sun? Possibly these are the stars we should be looking for to find intelligent life?

---

Merged post follows:

Consecutive posts merged

BTW, even though the OP did indeed get his wires crossed this should not be in Pseudoscience, I think it's a reasonable line of inquiry.

[D H]

It is a reasonable line of speculation.

 

The OP's style of presenting speculation as scientific fact is a bit irksome. That, coupled with the fact the OP can't get his facts straight (Tachibana and Huss found Nickel-60, not Iron-60¹) and can't even get his speculations straight (Type II versus Type IA supernova), is what motivated me to move this to speculations.

 

Note well the title of the subforum to which I moved this thread: "Pseudoscience and Speculations". It is perhaps unfortunate that Science Forums lumps the two categories together. The argument for lumping them together: Where is the boundary between the two?

 

============

Footnote:

 

¹ The half-life of Iron-60 is somewhere between 1.5 million years (old value) or 2.3 million years (somewhat disputed new number). Even with the longer half life, and even if the Earth was 100% Iron-60 4.6 billion years ago, there would be zero atoms of Iron-60 left today. It would all have decayed to Nickel 60. That is of course what Tachibana and Huss found. A finding of Iron-60 itself rather than its decay products would have been a sign of some much more recent supernova.

[swansont]

Note well the title of the subforum to which I moved this thread: "Pseudoscience and Speculations". It is perhaps unfortunate that Science Forums lumps the two categories together. The argument for lumping them together: Where is the boundary between the two?

 

D H is correct in pointing this out.

 

A post which simply asks a question would remain in a science forum. However, a post which attempts to answer, outside of mainstream science, is speculation. If the supporting argument proves to be supported by mainstream science, a speculative thread can be moved back.

 

Widdekind, please keep this in mind. Also, please review the rules, specifically rules 2.5, 2.8 and 2.10.