scholarly journals Neutron star deformability with hyperonization in density-dependent relativistic mean-field models

2021 ◽  
Vol 104 (6) ◽  
Author(s):  
W. Z. Shangguan ◽  
Z. Q. Huang ◽  
S. N. Wei ◽  
W. Z. Jiang
Keyword(s):  
Neutron Star ◽  
Mean Field ◽  
Density Dependent ◽  
Relativistic Mean Field ◽  
Mean Field Models

scholarly journals Properties of rotating neutron star in density-dependent relativistic mean-field models

2020 ◽  
pp. 2150001
Author(s):  
Rashid Riahi ◽  
Seyed Zafarollah Kalantari
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Quadrupole Moment ◽  
Stability Region ◽  
Equations Of State ◽  
Mean Field ◽  
Low Frequency ◽  
Density Dependent ◽  
Relativistic Mean Field ◽  
Limit Value

Equilibrium sequences were developed for rotating neutron stars in the relativistic mean-field interaction framework using four density-dependent equations of state (EOSs) for the neutron star matter. These sequences were constructed for the observed rotation frequencies of 25, 317, 346, 716 and 1122[Formula: see text]Hz. The bounds of sequences, the secular axisymmetric instability, static and Keplerian sequences were calculated in each model to determine the stability region. The gravitational mass, quadrupole moment, polar, forward and backward redshifts, and Kerr parameter were calculated according to this stability region, and the allowable range of these quantities was then determined for each model. According to the results, DDF and DD-ME[Formula: see text] were unable to properly describe the low-frequency neutron stars, PSR J0348+432, PSR J1614-2230 and PSR J0740+6620 rotate at a frequency of 25, 317 and 346[Formula: see text]Hz, respectively. On the other hand, all the selected EOSs properly described the rotation of PSR J1748-244ad and PSR J1739-285 at a frequency of 716 and 1122[Formula: see text]Hz, respectively. The mass of these stars was, therefore, in the range of [Formula: see text] and [Formula: see text], respectively. The polar, forward and backward redshifts, and the quadrupole moment were calculated in all the selected rotating frequencies and the Keplerian sequence. The results were consistent with observations. Confirming the mass of [Formula: see text] for EXO 0748-676, our result, [Formula: see text], will be close to the observed value, and the EOSs used in this study properly describe this star. Interestingly, the extremum of Kerr parameter, polar, forward and backward redshifts in all models reached constant values of, [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text], respectively. These behaviors of redshifts and Kerr parameter are approximately independent of EOS. The observed behaviors must evaluate by other EOSs to find universal relations for these quantities. Also, a limit value was found for each of these parameters. In this case where these parameters are greater than the limit value, the star can rotate at a frequency equal to or greater than [Formula: see text][Formula: see text]Hz.

scholarly journals Hyperons in neutron star matter within relativistic mean-field models

2015 ◽  
Vol 46 (5) ◽  
pp. 830-834 ◽  
Author(s):  
M. Oertel ◽  
C. Providencia ◽  
F. Gulminelli ◽  
A. R. Raduta
Keyword(s):  
Neutron Star ◽  
Mean Field ◽  
Neutron Star Matter ◽  
Relativistic Mean Field ◽  
Mean Field Models

scholarly journals Beta Equilibrium Under Neutron Star Merger Conditions

Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 399
Author(s):  
Mark G. Alford ◽  
Alexander Haber ◽  
Steven P. Harris ◽  
Ziyuan Zhang
Keyword(s):  
Neutron Star ◽  
Nuclear Matter ◽  
Equilibrium Condition ◽  
Mean Field ◽  
Temperature Correction ◽  
Nonzero Temperature ◽  
Relativistic Mean Field ◽  
Mean Field Models ◽  
Relativistic Dispersion ◽  
Correct Calculation

We calculate the nonzero-temperature correction to the beta equilibrium condition in nuclear matter under neutron star merger conditions, in the temperature range 1MeV<T≲5MeV. We improve on previous work using a consistent description of nuclear matter based on the IUF and SFHo relativistic mean field models. This includes using relativistic dispersion relations for the nucleons, which we show is essential in these models. We find that the nonzero-temperature correction can be of order 10 to 20 MeV, and plays an important role in the correct calculation of Urca rates, which can be wrong by factors of 10 or more if it is neglected.

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