scholarly journals On the Concept of Gravito-Rotational Acceleration and its Consequences for Compact Stellar Objects

2021 ◽  
Author(s):  
Mohamed Elmansour Hassani
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Orbital Motion ◽  
Rotational Acceleration ◽  
Gravitational Radius ◽  
Material Body ◽  
Stellar Objects ◽  
Gravitational Action ◽  
Theories Of Gravity ◽  
Previous Series

In a previous series of papers relating to the Combined Gravitational Action (CGA), we have exclusively studied orbital motion without spin. In the present paper, we apply CGA to any self-rotating material body, i.e., an axially spinning massive object, which itself may be locally seen as a gravito-rotational source because it is capable of generating the gravito-rotational acceleration, which seems to be unknown to previously existing theories of gravity. The consequences of such an acceleration are very interesting, particularly for Compact Stellar Objects. Independently of the equation of state, it is found that the minimum radius of a stable neutron star is three times its gravitational radius, Rmin = 3GMNS/c2, and its critical and maximum internal magnetic field strength cannot exceed the value of 3×1018 G.

scholarly journals Concept of Gravito-Rotational Acceleration and its Consequences for Compact Stellar Objects

2021 ◽  
Author(s):  
Mohamed Hassani
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Equation Of State ◽  
Orbital Motion ◽  
Rotational Acceleration ◽  
Material Body ◽  
Stellar Objects ◽  
Gravitational Action ◽  
Theories Of Gravity ◽  
Previous Series

In a previous series of papers relating to the Combined Gravitational Action (CGA), we have exclusively studied orbital motion without spin. In the present paper, we apply CGA to any self-rotating material body, i.e., an axially spinning massive object, which itself may be locally seen as a gravito-rotational source because it is capable of generating the gravito-rotational acceleration, which seems to be unknown to previously existing theories of gravity. The consequences of such an acceleration are very interesting, particularly for Compact Stellar Objects. Independently of the equation of state, it is found that the critical and maximum internal magnetic field strength of a stable neutron star cannot exceed the value of 3x1018G.

scholarly journals A Model for the Double System Containing the X-Ray Pulsar Her X-1

1975 ◽  
Vol 67 ◽  
pp. 497-497
Author(s):  
G. S. Bisnovatyi-Kogan ◽  
B. V. Komberg
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Orbital Motion ◽  
Solid Angle ◽  
Central Star ◽  
X Ray ◽  
Opposite Case ◽  
Narrow Angle ◽  
The Earth ◽  
Double System

A model for the double system with the X-ray source Her X-1 is considered. It is supposed that the central star has a sufficiently strong magnetic field for the outflow of the matter to occur in jets. When the neutron star is in the jet the optical depth τx attributable to the X-ray emission due to Compton scattering is greater than unity and the solid angle of the emitted X-radiation is broad, ∼ 180°. In the opposite case, τx < 1, there is a narrow angle of emission and the radiation falls on to the star and is not observed on the Earth. The motion of the neutron star relative to the jet is due to nonsynchronization between the orbital motion and rotation of the central star. If the duration of the whole orbit around the central star is 35 days and the dimension of the jet is about 1/3 of the orbit, then such a model explains features connected with the 35-day cycle.

scholarly journals On Possible Reduction of Equilibrium Radius of a Neutron Star Influenced by Superstrong Magnetic Field

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Vladimir V. Skobelev
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Electron Gas ◽  
Necessary Condition ◽  
Superstrong Magnetic Field ◽  
Stellar Objects ◽  
New Class ◽  
Short Period ◽  
Equilibrium Radius ◽  
Field Influence

Necessary condition forβ-decay suppression of a neutron in degenerate magnetized electron gas is formulated. Based on this, it is shown that, in superstrong magnetic field, equilibrium radius of a neutron star is approximately several times smaller than without the field influence. Therefore, we can make a prediction that in short-period pulsars, such fields can be observed. In fact, possible existence of new class of stellar objects is noted, the objects with superstrong magnetic field and supersmall radius about 1 km which we namedminimagnetars. They can be detected by gravitational red shift of their radiation.

scholarly journals Effect of magnetic field on the burning of a neutron star

2018 ◽  
Vol 27 (10) ◽  
pp. 1850083 ◽  
Author(s):  
Ritam Mallick ◽  
Amit Singh
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Initial Density ◽  
Considerable Effect ◽  
Magnetic Axis ◽  
Small Window ◽  
Exothermic Process ◽  
Text Density ◽  
The Magnetic Field ◽  
Observational Aspect

In this paper, we present the effect of a strong magnetic field in the burning of a neutron star (NS). We have used relativistic magneto-hydrostatic (MHS) conservation equations for studying the PT from nuclear matter (NM) to quark matter (QM). We found that the shock-induced phase transition (PT) is likely if the density of the star core is more than three times nuclear saturation ([Formula: see text]) density. The conversion process from NS to quark star (QS) is found to be an exothermic process beyond such densities. The burning process at the star center most likely starts as a deflagration process. However, there can be a small window at lower densities where the process can be a detonation one. At small enough infalling matter velocities the resultant magnetic field of the QS is lower than that of the NS. However, for a higher value of infalling matter velocities, the magnetic field of QM becomes larger. Therefore, depending on the initial density fluctuation and on whether the PT is a violent one or not the QS could be more magnetic or less magnetic. The PT also have a considerable effect on the tilt of the magnetic axis of the star. For smaller velocities and densities the magnetic angle are not affected much but for higher infalling velocities tilt of the magnetic axis changes suddenly. The magnetic field strength and the change in the tilt axis can have a significant effect on the observational aspect of the magnetars.

scholarly journals An Emission Line in the Hard X-Ray Spectrum of Hercules X-1: Quantized Cyclotron Emission from the Neutron Star

1977 ◽  
Vol 43 ◽  
pp. 34-34
Author(s):  
W. Pietsch ◽  
C. Reppin ◽  
R. Staubert ◽  
J. Truemper ◽  
W. Voges ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Second Harmonic ◽  
Narrow Line ◽  
Electron Cyclotron Emission ◽  
Polar Cap ◽  
Astrophysical Application ◽  
X Ray ◽  
Cyclotron Emission

A four hour balloon observation of HERC X-l during the 'On-state' in the 35 day cycle was performed on May 3rd, 1976. The 1.24 second pulsations show a pulsed fraction of 58 ± 8% in the 18-31 KeV interval. A pulsed flux (1.24 sec) was discovered in the 31-88 KeV interval with a pulsed fraction of 51 ± 14%. The spectrum of the pulsed flux can be represented up to 50 KeV by an exponential distribution with KT approximately 8 KeV. At approximately 58 KeV a strong and narrow line feature occurs which we interpret as electron cyclotron emission (ΔN = 1 Landau transition) from the polar cap plasma of the rotating neutron star. The corresponding magnetic field strength is approximately 5 x 1012 Gauss, neglecting gravitational red shift. There is evidence for a second harmonic at approximately 110 KeV (ΔN = 2 ).The astrophysical application of this discovery will be discussed in some detail.

scholarly journals Moment of inertia of neutron star crust in alternative and modified theories of gravity

2016 ◽  
Vol 94 (2) ◽  
Author(s):  
Kalin V. Staykov ◽  
K. Yavuz Ekşi ◽  
Stoytcho S. Yazadjiev ◽  
M. Metehan Türkoğlu ◽  
A. Savaş Arapoğlu
Keyword(s):  
Neutron Star ◽  
Moment Of Inertia ◽  
Modified Theories Of Gravity ◽  
Neutron Star Crust ◽  
Theories Of Gravity
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