Re: Article: "Sun is Mostly Iron, Not Hydrogen"

From: Anders Sandberg (asa@nada.kth.se)
Date: Wed Jan 09 2002 - 07:49:52 MST

On Wed, Jan 09, 2002 at 07:44:29AM -0500, Louis Newstrom wrote:
> From: "Anders Sandberg" <asa@nada.kth.se>
> >
> > I'm not an astrophysicist :-), but it seems that if this claim holds
> > true we have to change not just models of the formation of the solar
> > system but also how stars work. I think Dr. Manuel better have some
> > extraordinary evidence up his sleeve besides unusual xenon abundancies
> > to convince people that an iron core wouldn't cause a cooling collapse.
>
> I agree. Since the sun has not expanded into a red giant, it is not fusing
> helium yet, let alone heavier elements. Also, iron is NOT fusable. (I
> don't know if it is not fusable at all, or if it is just not fusable in the
> largest theoretical star, which is about 200 solar masses.)

You can fuse iron atoms, but the reaction is endothermic. So when this
happens, the star core cools. There are other nuclear processes
involving iron too, and all are endothermic and hence tend to cool the
star, causing it to compress.

We better learn to use iron for nanomachines, because that is what we
are going to end up with.

> I also would like to know what "strange xenon" is, as opposed to "normal
> xenon".

http://www.lpi.usra.edu/meetings/metsoc2000/pdf/5230.pdf :

WHAT IS ISOTOPICALLY STRANGE XENON?

  D. Heymann, Department of Geology and Geophysics, Rice University, Houston TX, USA.

Isotopically strange xenon (ISX) is strongly enriched in the p- and
r-isotopes relative to solar and terrestrial xenon [1]. However, these
`excess' components have never been separated from one another, nor have
they ever been made free of s-components. It was argued that the excess
p- and r- components had formed in supernovae and had been ion-
implanted into nanodiamonds [2]. It is argued here that ISX with the
smallest observed 130 Xe/ 136 Xe is a fundamental galactic Xe gas which
formed when p- and r-, and s- components were cycled through C-rich
stars and implanted into diamonds with kinetic energies on the order of
1 keV in stellar winds.

References:
[1] Lewis R. S. et al. (1975) Science, 190, 1251­1262.

[2] Lewis R. S. et al. (1987) Nature, 326, 160­162. 63rd Annual
Meteoritical Society Meeting 5230.pdf 

-- 
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Anders Sandberg                                      Towards Ascension!
asa@nada.kth.se                            http://www.nada.kth.se/~asa/
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