PDA

View Full Version : Bahcall Paper on Solar Abundance Uncertainties



antoniseb
2004-Dec-07, 02:14 AM
This is a paper for the few of us who are thinking about the Sun, and what it's made of, and what we know about it. The paper is 46 pages long, double spaced, and talks about haw small variations in the surface abundance are big factors in the expected neutrino flux.

How Do Uncertainties in the Surface Chemical Composition of the Sun Affect the Predicted Solar Neutrino Fluxes? (http://www.arxiv.org/PS_cache/astro-ph/pdf/0412/0412096.pdf)

I read sections one and seven, as Bahcall suggested in section one.

om@umr.edu
2004-Dec-07, 04:54 PM
Thanks, Anton, for posting an interesting paper.

I hope the new paper about "Uncertainties in the Surface Chemical Composition of the Sun" will encourage UT Readers to ponder the much larger "Uncertainties in the Internal Chemical Composition of the Sun". That is where solar neutrinos likely originate.

Regretfully, the paper does not even mention measurements showing mass separation in the Sun causes the "Surface Chemical Composition of the Sun" to consist almost entirely of the two lightest elements, H and He.

Those results are shown in 4 Figures and a Summary on the upper right side of my web page.

http://www.umr.edu/~om

They are also discussed in the Iron Sun thread,

http://www.universetoday.com/forum/index.p...pic=2544&st=240 (http://www.universetoday.com/forum/index.php?showtopic=2544&st=240)

where I will post Bahcall's latest paper.

Again, Anton, thanks for bringing this interesting paper to our attention.

With kind regards,

Oliver

antoniseb
2004-Dec-07, 05:08 PM
Originally posted by om@umr.edu@Dec 7 2004, 04:54 PM
thanks for bringing this interesting paper to our attention.
I have always believed that we must try to be aware of both what the current best models are, and the scale of change that happens to X when you wiggle Y in each model. I have no problem with him not mentioning mass fractionation since I don't think its that big a factor in the current sun, but I was surprised that there was a lot of effort put into saying how much we needed accurate data about composition, and little about whether the Genesis data might satisfy this interest.

om@umr.edu
2004-Dec-07, 05:28 PM
Originally posted by antoniseb@Dec 7 2004, 05:08 PM
1. I have no problem with him not mentioning mass fractionation since I don't think its that big a factor in the current sun, but

2. I was surprised that there was a lot of effort put into saying how much we needed accurate data about composition, and little about whether the Genesis data might satisfy this interest.
Hi, Anton.

1. A model which considers solar mass separation yields <38% of the neutrino flux expected from the standard solar model.

See "Is There A Deficit of Solat Neutrinos ?"

http://web.umr.edu/~om/abstracts2004/om-so...ar-neutrino.pdf (http://web.umr.edu/~om/abstracts2004/om-solar-neutrino.pdf)

2. The NASA status report suggests that isotope data on N and O may be the only forthcoming results from the Genesis Mission.

http://www.nasa.gov/mission_pages/genesis/...sis-093004.html (http://www.nasa.gov/mission_pages/genesis/media/genesis-093004.html)

The report claims " . . .things are looking very, very good" and that "isotopic ratios of oxygen and nitrogen . . . are the mission&#39;s most important science goal.

Those results will provide little or no useful information on the internal composition of the Sun.

With kind regards,

Oliver
http://www.umr.edu/~om