Influence of the Change in the Galactic-Nucleosynthesis Rate before the Formation of Solar System on the Determination o
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CLEI Theory
Influence of the Change in the Galactic-Nucleosynthesis Rate before the Formation of Solar System on the Determination of Age of The Universe I. V. Panov1), 2), 3)* , Yu. S. Lyutostansky3), and M. Eichler4) Received July 13, 2018; revised July 13, 2018; accepted July 13, 2018
Abstract—The dependence of the region of physically admissible values of uranium–thorium isotope ratios on the short-term change in nucleosynthesis rate, which increases just before the formation of the Solar system, is studied. An additional admissible region associated with the presence of the isotope 244 Pu and the effect of this region on the calculation of the age of the Universe, TU , are considered within galacticnucleosynthsis theory. The size of the admissible region and its dependence on the short-term increase in the rate of heavy-element production (enhancement of nucleosynthsis) before the formation of the Solar System is discussed along with the consistency of the predictions for the above ratios with the region of admissible values. It is shown that an enhancement of nucleosynthesis is necessary for attaining agreement between the calculated ratios of cosmochronometer nuclei and the region of admissible values, but this enhancement should not lead to an increase in the abundances of heavy elements that is greater than 1 to 3% of the total amount of synthesized heavy elements. DOI: 10.1134/S1063778819010125
1. INTRODUCTION
models, the relation between H0 and TU is more complicated than H −1 ∼ t and depends on the metric, density, cosmological constant, etc., with the result that there appears a spread of TU (for an overview, see [5]). Different astrophysical means for evaluating the age of the Universe rely on determining it from the lifetimes of spherical constellations and galactic-halo subgiants (referring to population II), as well as of the coldest white dwarfs. For example, the age of stellar constellations is determined from an analysis of the stellar composition and Hertzsprung–Russell diagram constructed for them. Upon employing additional data on the content of helium and other observational results obtained from the dynamics of galaxy groups, the range of values for the age of the Universe was found in [6] to be 13.5 ≤ TU ≤ 15.5 billion years. The largest uncertainty in this method stems from a determination of distances and, hence, the mass– luminosity relation, which forms the basis for constructing the diagram—the respective error is 2 to 3 billion years. This error is compatible with recent observations, which, for the HD84937, HD132475, and HD140283 objects, yielded age values of, respectively, TU 12.08 ± 0.14, 12.56 ± 0.46, and 14.27 ± 0.38 billion years [7]. In [8], the minimum estimate of the age TU is about 11.2 billion years, while the estimated value of TU is 13.4 billion years. An estimation of the age TU on the basis of the temperature of the coldest white dwarfs yields values
A nuclear-physics method based on measuring time variations of the ratios of the abundances of long-lived uranium and t
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