330 research outputs found
Recent Work on Standard Solar Models
Recent results on standard solar models are reviewed. I shall summarize
briefly three of the themes that I stressed at the Neutrino '92 Conference: 1)
Different solar model codes give the same answers when the same input data are
used; 2) Improved calculations of standard solar models include helium
diffusion, the Livermore radiative opacity, the meteoritic iron abundance, and
a variety of other corrections; and 3) There are a few basic rules that should
be followed in using standard solar models. At the Neutrino '92 Conference, I
reviewed in more detail the recent work on standard solar models by Marc
Pinsonneault and myself. This work has by now appeared in print (Rev. Mod.
Phys. 64, 885, 1992, hereafter Paper I, and ApJ Letters, 69, 717, 1992, Paper
II). Therefore, there is no need for me to repeat the details here.Comment: 4 pages, Institute for Advanced Study number AST 92/5
What Do Solar Models Tell Us About Solar Neutrino Experiments?
If the published event rates of the chlorine and Kamiokande solar neutrino
experiments are correct, then the energy spectrum of neutrinos produced by the
decay of B in the sun must be different from the energy spectrum determined
from laboratory nuclear physics measurements. This change in the energy
spectrum requires physics beyond the standard electroweak model. In addition,
the GALLEX and SAGE experiments, which currently have large statistical
uncertainties, differ from the predictions of the standard solar model by and , respectively.Comment: 4 pages (LaTeX file, figures not included
Solar Neutrinos: Where We Are, Where We Are Going
This talk answers a series of questions. Why study solar neutrinos? What does
the combined standard model (solar plus electroweak) predict for solar
neutrinos? Why are the calculations of neutrino fluxes robust? What are the
three solar neutrino problems? What have we learned in the first thirty years
of solar neutrino research? For the next decade, what are the most important
solvable problems in the physics of solar neutrinos? What are the most
important problems in the astrophysics of solar neutrinos?Comment: uuencoded Z-compressed postscript file; 36 pages with figures. To be
published in the Astrophysical Journa
Solar Neutrinos: What Next?
I summarize the current state of solar neutrino research and then give my
answer to the question: What should we do next?Comment: NNN99 Workshop, viewgraphs and related information at
http://www.sns.ias.edu/~jn
Solar Neutrinos. I. Theoretical
The principal energy source for main-sequence
stars like the sun is believed to be the fusion, in
the deep interior of the star, of four protons to
form an alpha particle. The fusion reactions
are thought to be initiated by the sequence ^1H(p,
e^(+)v)^2H(p,γ)^(3)He and terminated by the following
sequences: (i) ^(3)He(^(3)He, 2p)^(4)He; (ii) ^(3)He(α,γ)^(7)Be(e^(-)v)^(7)Li(p,α)^(4)He; and (iii) ^(3)He(α,γ)^(7)Be(p,γ)^(8)B(e^(+)v)^(8)Be*(α)^(4)He. No direct evidence for the existence of nuclear reactions in the interiors of stars has yet been obtained because the mean free path for photons emitted in the center of a star is typically less than 10^(-10) of the radius of
the star. Only neutrinos, with their extremely
small interaction cross sections, can enable us
to see into the interior of a star and thus verify
directly the hypothesis of nuclear energy generation
in stars
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