2017 ◽  
Vol 26 (04) ◽  
pp. 1750015 ◽  
Author(s):  
Yeunhwan Lim ◽  
Chang Ho Hyun ◽  
Chang-Hwan Lee

In this paper, we investigate the cooling of neutron stars with relativistic and nonrelativistic models of dense nuclear matter. We focus on the effects of uncertainties originated from the nuclear models, the composition of elements in the envelope region, and the formation of superfluidity in the core and the crust of neutron stars. Discovery of [Formula: see text] neutron stars PSR J1614−2230 and PSR J0343[Formula: see text]0432 has triggered the revival of stiff nuclear equation of state at high densities. In the meantime, observation of a neutron star in Cassiopeia A for more than 10 years has provided us with very accurate data for the thermal evolution of neutron stars. Both mass and temperature of neutron stars depend critically on the equation of state of nuclear matter, so we first search for nuclear models that satisfy the constraints from mass and temperature simultaneously within a reasonable range. With selected models, we explore the effects of element composition in the envelope region, and the existence of superfluidity in the core and the crust of neutron stars. Due to uncertainty in the composition of particles in the envelope region, we obtain a range of cooling curves that can cover substantial region of observation data.


1986 ◽  
Vol 138 (6) ◽  
pp. 293-362 ◽  
Author(s):  
E. Moya de Guerra

Author(s):  
E. D. Arthur ◽  
M. B. Chadwick ◽  
G. M. Hale ◽  
P. G. Young
Keyword(s):  

2021 ◽  
Vol 36 (08) ◽  
pp. 2150051
Author(s):  
H. Özdoğan ◽  
İsmail Hakki Sarpün ◽  
Mert Şekerci ◽  
Abdullah Kaplan

[Formula: see text], a known gamma emitter, is used for many medical purposes such as imaging of myocardial metastases. It can be produced by using different nuclear reactions. In this study, the reactions of [Formula: see text]Ag([Formula: see text]2n)[Formula: see text], [Formula: see text](p,[Formula: see text]n)[Formula: see text], [Formula: see text](p,[Formula: see text]2n)[Formula: see text], [Formula: see text](p,[Formula: see text]3n)[Formula: see text] and [Formula: see text](p,[Formula: see text]4n)[Formula: see text], which are the production routes of [Formula: see text], were investigated. Production cross-section calculations were performed by using equilibrium and pre-equilibrium models of TALYS 1.95 and EMPIRE 3.2 nuclear reaction codes. Hauser–Feshbach Model was appointed in both codes for calculations of equilibrium approximations. Exciton and Hybrid Monte Carlo Simulation (HMS) models were used in the EMPIRE 3.2, whereas Two-Component Exciton and Geometry Dependent Hybrid Model, which is implemented to TALYS code, has been used in the TALYS 1.95 for pre-equilibrium reactions. Also, a weighting matrix of the nuclear models was obtained by using statistical variance analysis. The optimum beam energy to obtain [Formula: see text] has been determined by using the results obtained from this weighting matrix.


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