Astronomy and Astrophysics for the 1980's, Volume 2 Reports of the Panels (1983) / Chapter Skim
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III. Laboratory Astrophysics
III. Laboratory Astrophysics
Pages 286-301
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From page 286... ...
There is a strong synergism between the physics of many terrestrial energy problems and the situations encountered in astronomical environments, and theoretical astrophysicists are often uniquely qualified to make important contributions to energy research as a result of their broad training in gas dynamics, plasma physics, atomic processes, and radiative-transfer theory. We recommend a continuing effort to strengthen the ties between the DOE institutions and the astrophysics community.
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From page 287... ...
offer unprecedented opportunities for the detailed study of the physical conditions of such varied environments as those of the dark interstellar clouds where star formation is in progress; the outer envelopes of stars (with associated stellar winds and mass loss) ; novae and supernovae; the accretion flow onto white dwarfs, neutron stars, and black holes in binary systems; and the nuclei of active galaxies and quasars.
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From page 288... ...
The techniques for the production of slowly moving beams will permit the measurement of cross sections for collision processes at the low temperatures occurring in molecular clouds and will provide a vital ingredient of theoretical models of molecular formation and the associated cooling processes. In planetary science, the need is urgent for spectroscopic information about a lengthy list of molecular species.
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From page 289... ...
Accurate molecular data would transform interstellar chemistry from a qualitatively attractive description of possibilities to quantitative diagnostic procedure and would lead to a realistic description of the role of chemical processes in cloud collapse and star formation. Rapid progress in laboratory and theoretical studies is technically possible on many fronts.
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From page 290... ...
There are five areas to which we wish to draw special attention, areas that we expect greatly to affect astrophysics in the coming decade: the solar neutrino question, stellar nucleosynthesis, supernova theory, cosmicray isotopic composition, and nuclear chronology. The solar neutrino problem remains one of the most per plexing in astrophysics, apparently striking at the very roots of our understanding of stars and stellar evolution.
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From page 291... ...
for the predicted neutrino flux, and it still remains on the order of three times the measured upper limit. It is of very high importance to re-examine carefully all the relevant cross sections and atomic-physics data that go into the nuclear reactions and stellar models.
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From page 292... ...
Numbers of recent experiments have revealed isotopic ratios that differ significantly from the solar-terrestrial ones, and future work promises to be very exciting. Questions that may be answered include the old one of whether the cosmic rays are accelerated from the material of the interstellar medium or from fresh supernova ejecta.
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From page 293... ...
The limits on the observed cosmic deceleration place restrictions on the sum of all neutrino masses, and the observed helium abundance limits the total number of neutrino flavors permitted within the framework of big-bang cosmology. Phase transitions may have occurred in the early Universe in which the electroweak gauge symmetry and the strong interaction chiral symmetry were successively broken.
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From page 294... ...
mese observations also yield insight into the particular nuclear astrophysical processes within supernovae, in the isotopic and chemical state of supernova debris and interstellar matter. Given reliable laboratory data on primitive solar-system materials (meteorites and comets)
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From page 295... ...
During the past decade, extended temporal and broadband spectroscopic studies carried out by x-ray astronomical satellites have led to the identification of specific compact x-ray sources as accreting neutron stars, black holes, or white dwarfs in close binary systems. Such sources provide a unique opportunity to study matter under extreme conditions not accessible in the terrestrial laboratory.
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From page 296... ...
high-density matter, which determines the behavior of collapsing cores, is probably crucial for the proper description of the supernova phenomenon and the production of supernova remnants. The behavior of condensed matter in superstrong magnetic fields may well determine the behavior of the pulsar phenomenon through its influence on the conductivity and effective work function of the neutron star surface.
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From page 297... ...
Increased availability of computing power will lead to substantial expansion in nonlinear modeling and in numerical experimentation. An effective strategy for astrophysical fluid dynamics and magnetohydrodynamics is the development of numerical techniques that are to be tested by comparison with critical laboratory experiments and analytic solutions and then used to extrapolate to otherwise inaccessible astrophysical conditions.
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From page 298... ...
Continued experimental studies of the properties of rotating superfluids are important to an understanding of neutron-star interiors. Other aspects of fluid dynamics are the coupling of convection and pulsation for application to variable stars, the interaction of fluid dynamics and spectral radiation for application to theory of spectral lines, the theory of drops and bubbles for application to the formation of dust through the liquid drop phase, and the dynamics of fluids with large molecular weights to allow simulations of small scale heights in the laboratory.
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From page 299... ...
NASA should recognize its larger responsibilities to the sciences that its missions help to illuminate and create a program of research in better balance with its essential objectives. RECOMMENDATION III.2: Because laboratory astrophysical processes are common to a wide range of energy-related researches, the Department of Energy should continue to recognize laboratory astrophysics as an appropriate area for funding support.
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From page 300... ...
We urge renewed and vigorous support by NBS of laboratory astrophysics. Astronomers demand and contribute to the development of a broad base of knowledge of fundamental atomic and molecular processes that is the proper concern of this agency.
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From page 301... ...
As a supplement to Recommendation 5, we encourage the creation of visiting fellowships, established on a regular basis, so that laboratory astrophysicists and astronomers may join institutions that maintain facilities for the support of research activities of interest to astronomy. The program at the Joint Institute for Laboratory Astrophysics has been a notable success.
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