scholarly journals Application of Regge Theory to Astronomical Objects

Physics ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 669-677
Author(s):  
Gurgen G. Adamian ◽  
Nikolai V. Antonenko ◽  
Horst Lenske ◽  
Vazgen V. Sargsyan
Keyword(s):  
Neutron Star ◽  
Binary Systems ◽  
Rotation Frequency ◽  
Moment Of Inertia ◽  
Clusters Of Galaxies ◽  
Observable Universe ◽  
Regge Theory ◽  
Instability Effect ◽  
Analytical Formulas ◽  
The Moment

Using the model based on the Regge-like laws, new analytical formulas are obtained for the moment of inertia, the rotation frequency, and the radius of astronomical non-exotic objects (planets, stars, galaxies, and clusters of galaxies). The rotation frequency and moment of inertia of a neutron star and the observable Universe are estimated. The estimates of the average numbers of stars and galaxies in the observable Universe are given. The Darwin instability effect in the binary systems (di-planets, di-stars, and di-galaxies) is also analyzed.

scholarly journals Identifying the formation mechanism of redback pulsars

2020 ◽  
Vol 493 (2) ◽  
pp. 2171-2177 ◽  
Author(s):  
M A De Vito ◽  
O G Benvenuto ◽  
J E Horvath
Keyword(s):  
Mass Transfer ◽  
Neutron Star ◽  
Formation Mechanism ◽  
Binary Systems ◽  
Close Binary ◽  
Formation Mechanisms ◽  
Orbital Periods ◽  
The Moment ◽  
Strong Evaporation ◽  
Theoretical Results

ABSTRACT We analyse the evolution of close binary systems containing a neutron star that lead to the formation of redback pulsars. Recently, there has been some debate on the origin of such systems and the formation mechanism of redbacks may still be considered as an open problem. We show that the operation of a strong evaporation mechanism, starting from the moment when the donor star becomes fully convective (or alternatively since the formation of the neutron star by accretion-induced collapse), produces systems with donor masses and orbital periods in the range corresponding to redbacks with donors appreciably smaller than their Roche lobes, i.e. they have low filling factors (lower than 0.75). Models of redback pulsars can be constructed assuming the occurrence of irradiation feedback. They have been shown to undergo cyclic mass transfer during the epoch at which they attain donor masses and orbital periods corresponding to redbacks, and stay in quasi-Roche lobe overflow conditions with high filling factors. We show that, if irradiation feedback occurs and radio ejection inhibits further accretion on to the neutron star after the first mass transfer cycle, the redback systems feature high filling factors. We suggest that the filling factor should be considered as a useful tool for discriminating among those redback formation mechanisms. We compare theoretical results with available observations and conclude that observations tend to favour models with high filling factors.

On the moment of inertia of a proto neutron star

2010 ◽  
Vol 34 (10) ◽  
pp. 1587-1592
Author(s):  
Zhao Xian-Feng ◽  
Zhang Hua ◽  
Jia Huan-Yu
Keyword(s):  
Neutron Star ◽  
Moment Of Inertia ◽  
The Moment ◽  
Proto Neutron Star

scholarly journals A Model for the Braking Indices of Pulsars

2017 ◽  
Vol 45 ◽  
pp. 1760036 ◽  
Author(s):  
Heitor O. de Oliveira ◽  
Rubens M. Marinho ◽  
Nadja S. Magalhães
Keyword(s):  
Energy Conservation ◽  
Rotation Frequency ◽  
Moment Of Inertia ◽  
Canonical Model ◽  
Time Varying ◽  
The Moment

Stars known as pulsars are generally modeled as magnetized spheres made of neutrons with high rotation frequency. It is known that such stars are spinning down and this braking is measured by a parameter, n, known as braking index. For the canonical model such parameter should have a single value for all pulsars: n = 3. However, from observations it is known that n diverges from 3. In this work, differently from the canonical model, we have hypothesized the existence of a variation of the moment of inertia of the star through a time-varying radius. Using energy conservation we find the values for the variation of the radius of our pulsar sample. Our results indicate that it may be reasonable to consider that the radius of pulsars can be changing with time.

Dielectrophoretic Rotation in Budding Yeast Cells

1980 ◽  
Vol 35 (11-12) ◽  
pp. 1111-1113 ◽  
Author(s):  
Maja Mischel ◽  
Ingolf Lamprecht
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Budding Yeast ◽  
Low Frequency ◽  
Rotation Frequency ◽  
Moment Of Inertia ◽  
Yeast Cells ◽  
Uniform Electric Field ◽  
The Moment

Abstract Rotation of budding yeast cells in an alternating non-uniform electric field of low frequency was investigated. Rotation frequency was found to be proportional to field strength above a threshold, and varied from cell to cell. The threshold is inversely correlated with the moment of inertia of the cells, while the slope of rotation frequency versus field strength increases with the moment. Rotation frequencies varied between 1 and 10 cycles per second. Clear differences between the dielectrophoretic behaviour of living and heat-inactivated yeast cells were observed.

scholarly journals Roles of crust and core in the tidal deformability of neutron stars

2019 ◽  
Vol 28 (09) ◽  
pp. 1950081 ◽  
Author(s):  
A. M. Kalaitzis ◽  
T. F. Motta ◽  
A. W. Thomas
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Dense Matter ◽  
Moment Of Inertia ◽  
Recent Measurement ◽  
Low Density ◽  
Important Constraint ◽  
The Moment

With the recent measurement of GW170817 providing constraints on the tidal deformability (TD) of a neutron star, it is very important to understand what features of the equation of state (EoS) have the biggest effect on it. We therefore study the contribution of the crust to the TD and the moment of inertia (MoI) of a neutron star for a variety of well-known EoS. It is found that the contributions to these quantities from the low-density crust are typically quite small and as a result the determination of the TD provides an important constraint on the EoS of dense matter.

PROPERTIES OF HOT NEUTRON STAR

2003 ◽  
Vol 12 (07) ◽  
pp. 1241-1254
Author(s):  
C. DAS ◽  
P. K. PANDA ◽  
M. ADHIKARY
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Matter ◽  
Moment Of Inertia ◽  
Gravitational Radius ◽  
Period Increase ◽  
Pion Condensation ◽  
Pure Neutron Matter ◽  
The Moment ◽  
Tov Equation

The properties of neutron star at temperatures 5 MeV, 10 MeV and 15 MeV are calculated by solving Tolmann–Oppenheimer–Volkoff (TOV) equation. The required equation of state of pure neutron matter is obtained using density dependent Sussex interaction. It is observed that maximum stable mass of the star corresponds to minimum gravitational radius for a given equation of state. Just like the limiting mass, limiting value of redshift, moment of inertia, Kepler frequency as well as Kepler period are observed in case of the neutron star. It is found that the star become somewhat 'massive' and 'fat' at higher temperatures. With the increase in temperature the moment of inertia and Kepler rotational period increase but redshift decreases and Kepler frequency slows down. We also predict that there is a possibility of pion condensation in pure neutron matter.

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