Thermonuclear Reaction Rates

Fowler, William A.; Caughlan, Georgeanne R.; Zimmerman, Barbara A.

doi:10.1146/annurev.aa.05.090167.002521

Cited by 668 publications

(509 citation statements)

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“…1) are gathered from an extensive survey of the literature. These data are fitted to standard, if very approximate, theoretical expectations concerning their energy dependence (typically a loworder polynomial, for the low-energy S-factor), which has been widely used in previous work [18][19][20][21]. Some arbitrary choices are made concerning inclusion and exclusion of data points in the fits, with a view to making these fits accurate over the energy range critical for BBN.…”

Section: Introductionmentioning

confidence: 99%

Estimating reaction rates and uncertainties for primordial nucleosynthesis

2000

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We present a Monte Carlo method for direct incorporation of nuclear inputs in primordial nucleosynthesis calculations. This method is intended to remedy shortcomings of current error estimation, by eliminating intermediate data evaluations and working directly with experimental data, allowing error estimation based solely on published experimental uncertainties. This technique also allows simple incorporation of new data and reduction of errors with the introduction of more precise data. Application of our method indicates that previous error estimates on the calculated abundances were too large by as much as a factor of three. Since uncertainties in the BBN calculation currently dominate inferences drawn from light-element abundances, the re-estimated errors have important consequences for cosmic baryon density, neutrino physics, and lithium depletion in halo stars. Our direct method allows detailed discussion of the status of the nuclear inputs, by identifying clearly the places where improved cross section measurements would be most useful. 26.35.+c, 98.80.Ft

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Section: Introductionmentioning

confidence: 99%

Estimating reaction rates and uncertainties for primordial nucleosynthesis

2000

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“…This is the thermally driven instability first discussed by Goldreich andSchubert (1967, 1968) and later by Fricke (1968). With this instability, angular momentum is transported toward the surface in outward and inward moving thin toruses, with a thickness in the 9 direction of only a few km.…”

Section: Physical Requirements For a Rapidly Rotating Corementioning

confidence: 89%

“…One is reminded of the example of the thermo-haline instability discussed by Goldreich and Schubert (1967). Here, essentially the same analysis as that used by Goldreich, Schubert and Fricke can be employed to 'prove' that the salt concentration must be greater at the bottoms of all oceans than at the tops.…”

Section: Physical Requirements For a Rapidly Rotating Corementioning

confidence: 96%

“…Thermally driven currents (Eddington-Sweet) may occur, as well as thermally driven instabilities (Goldreich and Schubert, 1967;1968).…”

Section: Physical Requirements For a Rapidly Rotating Corementioning

confidence: 99%

“…Thus circulation currents or oscillating motion in the 9 direction would inhibit the instability and stabilize the rotation. Another means of stabilizing the rotation is provided by a gradient in mean molecular weight (Colgate, 1968;Goldreich and Schubert, 1968).…”

Section: Physical Requirements For a Rapidly Rotating Corementioning

confidence: 99%

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The Rotation of the Sun (Review Paper)

Dicke

1970

International Astronomical Union Colloquium

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Abstract. The author's 1964 article in Nature on the sun's rotation is rediscussed in the light of new data. This article suggested that the sun might be oblate because of a gravitational quadrupole moment induced by a core rotating with a period < 2 days. Angular momentum lost from the core by molecular diffusion was assumed to be transferred to the solar wind which kept the sun's surface rotating slowly. The estimated solar wind torque was found to be in good agreement with the torque calculated from a solution of the diffusion equation.Subsequent to the 1964 paper the oblateness was observed. Also the solar wind torque was 'observed' to be in good agreement with the early estimate. New observations discussed here seem to be important if the sun can be safely assumed to be a typical star and not an exception. It has been found by Kraft (1967) that very young solar type stars (Pleiades) are rotating with roughly the same angular velocity postulated for the solar core. As determined from observations on the Hyades in comparison with the Pleiades, the rotation of young solar-type stars is slowing at a rate consistent with a stellar wind torque equal to that of the solar wind acting on the outer 20-30 % of the star by radius. The slowing of the rotation in young stars is accompanied by a depletion of lithium, but not berylium. This implies that only the outer 45 % of the star by radius, or 5 % by mass, is slowed by the solar wind. The rapid rotation of the inner 95 % of the mass is sufficient to generate the observed oblateness. The rate of depletion of lithium, determined from observations on solar-type stars of various ages, is consistent with the rate of angular momentum loss assuming a reasonable model for the transport of angular momentum to the convective zone.

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