scholarly journals The second Maxwell’s relativistic equations of a rapidaly rotating neutron star, based on ZAMO framework (zero angular momentum observers)

2017 ◽  
Vol 1 (1) ◽  
pp. 13
Author(s):  
Atsnaita Yasrina ◽  
Nugroho Adi Pramono ◽  
Eny Latifah ◽  
Hari Wisodo
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Differential Equations ◽  
Neutron Stars ◽  
Maxwell’S Equation ◽  
Rotating Star ◽  
Fundamental Equations ◽  
Relativistic Equations ◽  
Maxwell's Equation

<p class="Abstract">The second Maxwell’s relativistic equations of a rapidaly rotating neutron star, based on ZAMO framework (Zero Angular Momentum Observers) has been formulated. The formulations obtained were epresented by differential equations in the radial, polar, and azimuthal components. The ZAMO basis is implemented because the neutron star reviewed as a rotating star. The second Maxwell’s equation is important to use as one of the fundamental equations to formulate relativistic magnetic fields dynamics of the neutron stars that rotate rapidly.</p>

The second Maxwell’s relativistic equations of a rapidaly rotating neutron star, based on ZAMO framework (zero angular momentum observers)

2017 ◽  
Vol 1 (1) ◽  
pp. 13
Author(s):  
Atsnaita Yasrina ◽  
Nugroho Adi Pramono ◽  
Eny Latifah ◽  
Hari Wisodo
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Differential Equations ◽  
Neutron Stars ◽  
Maxwell’S Equation ◽  
Rotating Star ◽  
Fundamental Equations ◽  
Relativistic Equations ◽  
Maxwell's Equation

<p class="Abstract">The second Maxwell’s relativistic equations of a rapidaly rotating neutron star, based on ZAMO framework (Zero Angular Momentum Observers) has been formulated. The formulations obtained were epresented by differential equations in the radial, polar, and azimuthal components. The ZAMO basis is implemented because the neutron star reviewed as a rotating star. The second Maxwell’s equation is important to use as one of the fundamental equations to formulate relativistic magnetic fields dynamics of the neutron stars that rotate rapidly.</p>

scholarly journals Onset of superconductivity and retention of magnetic fields in cooling neutron stars

2017 ◽  
Vol 13 (S337) ◽  
pp. 213-216
Author(s):  
Wynn C. G. Ho ◽  
Nils Andersson ◽  
Vanessa Graber
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Minimum Energy ◽  
Meissner Effect ◽  
Energy Conditions ◽  
Field Diffusion ◽  
Neutron Star Cooling ◽  
Proton Pairing

AbstractA superconductor of paired protons is thought to form in the core of neutron stars soon after their birth. Minimum energy conditions suggest that magnetic flux is expelled from the superconducting region due to the Meissner effect, such that the neutron star core retains or is largely devoid of magnetic fields for some nuclear equation of state and proton pairing models. We show via neutron star cooling simulations that the superconducting region expands faster than flux is expected to be expelled because cooling timescales are much shorter than timescales of magnetic field diffusion. Thus magnetic fields remain in the bulk of the neutron star core for at least 106 − 107yr. We estimate the size of flux free regions at 107yr to be ≲ 100m for a magnetic field of 1011G and possibly smaller for stronger field strengths.

scholarly journals Accretion onto Magnetized Neutron Stars: Polar Cap Flow and Centrifugally Driven Winds

1987 ◽  
Vol 125 ◽  
pp. 207-225
Author(s):  
Jonathan Arons
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Neutron Stars ◽  
Orbital Evolution ◽  
Time Dependent ◽  
Polar Cap ◽  
Periodic Oscillations ◽  
X Ray ◽  
Polar Caps ◽  
Basic Concepts

Some basic concepts of accretion onto the polar caps of magnetized neutron stars are reviewed. Preliminary results of new, multidimensional, time–dependent calculations of polar cap flow are outlined, and are used to suggest the possible observability of fluctuations in the X–ray intensity of accretion powered pulsars on time scales of 10–100 msec. The possible relevance of such fluctuations to Quasi–Periodic oscillations is suggested. Basic concepts of the interaction between a disk and the magnetosphere of a neutron star are also discussed. Some recent work on the disk–magnetosphere interaction is outlined, leading to the suggestion that a neutron star can lose angular momentum by driving some or all of the mass in the disk off as a centrifugally driven wind. The relevance of such mass loss to the orbital evolution of the binary is pointed out.

scholarly journals The Pulsar Magnetic Window

1981 ◽  
Vol 95 ◽  
pp. 103-105 ◽  
Author(s):  
C. S. Shukre ◽  
V. Radhakrishnan
Keyword(s):  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Gamma Rays ◽  
Narrow Range ◽  
Spark Discharges ◽  
Sutherland Model ◽  
Good Agreement ◽  
Field Strengths

Triggering of the spark discharges in the Ruderman and Sutherland model by background gamma rays is shown to be effective only within a narrow range of neutron star magnetic fields centred on 2.5 × 1012 gauss. This calculated range of field strengths is in good agreement with ‘observed’ values, suggesting that (a) such triggering is operative, and (b) that neutron stars with much stronger fields do not function as pulsars.

scholarly journals Angular Momentum Transport and Mixing by Magnetic Fields

2004 ◽  
Vol 215 ◽  
pp. 356-365 ◽  
Author(s):  
H. C. Spruit
Keyword(s):  
Angular Momentum ◽  
Magnetic Fields ◽  
Internal Gravity Waves ◽  
Momentum Transport ◽  
Dynamo Model ◽  
Angular Momentum Transport ◽  
Field Amplification ◽  
Amplification Loop ◽  
Transport And Mixing ◽  
Rotating Star

Magnetic fields can be created in stably stratified (non-convective) layers in a differentially rotating star. A magnetic instability in the toroidal field (wound up by differential rotation) replaces the role of convection in closing the field amplification loop. A dynamo model is developed from these ingredients, and applied to the problem of angular momentum transport in stellar interiors. It produces a predominantly horizontal field. The process is found to be more effective in transporting angular momentum than the known hydrodynamic mechanisms, with the possible exception of transport by internal gravity waves.

scholarly journals Thermal luminosities of cooling neutron stars

2020 ◽  
Vol 496 (4) ◽  
pp. 5052-5071 ◽  
Author(s):  
A Y Potekhin ◽  
D A Zyuzin ◽  
D G Yakovlev ◽  
M V Beznogov ◽  
Yu A Shibanov
Keyword(s):  
Spectral Analysis ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Cooling Curves ◽  
Middle Aged ◽  
Superdense Matter ◽  
Strong Magnetic Fields ◽  
Stellar Core ◽  
Neutron Star Cooling

ABSTRACT Ages and thermal luminosities of neutron stars, inferred from observations, can be interpreted with the aid of the neutron star cooling theory to gain information on the properties of superdense matter in neutron-star interiors. We present a survey of estimated ages, surface temperatures, and thermal luminosities of middle-aged neutron stars with relatively weak or moderately strong magnetic fields, which can be useful for these purposes. The catalogue includes results selected from the literature, supplemented with new results of spectral analysis of a few cooling neutron stars. The data are compared with the theory. We show that overall agreement of theoretical cooling curves with observations improves substantially for models where neutron superfluidity in stellar core is weak.

scholarly journals Neutron Star Properties with Relativistic Equations of State

1998 ◽  
Vol 07 (03) ◽  
pp. 301-339 ◽  
Author(s):  
H. Huber ◽  
F. Weber ◽  
M. K. Weigel ◽  
Ch. Schaab
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Equations Of State ◽  
Neutron Star Matter ◽  
Hartree Fock ◽  
Standard Neutron ◽  
Relativistic Equations

We study the properties of neutron stars adopting relativistic equations of state of neutron star matter, calculated in the framework of the relativistic Brueckner–Hartree–Fock approximation for electrically charge neutral neutron star matter in beta–equilibrium. For higher densities more baryons (hyperons etc.) are included by means of the relativistic Hartree– or Hartree–Fock approximation. The special features of the different approximations and compositions are discussed in detail. Besides standard neutron star properties special emphasis is put on the limiting periods of neutron stars, for which the Kepler criterion and gravitation–reaction instabilities are considered. Furthermore the cooling behaviour of neutron stars is investigated, too. For comparison we also give the outcome for some nonrelativistic equations of state.

scholarly journals SGRs and AXPs: Evidence for Delayed Amplification of Magnetic Field after Neutron Star Formation?

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Denis Leahy ◽  
Rachid Ouyed
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Birth Rate ◽  
Massive Stars ◽  
Robust Estimator ◽  
High Magnetic Fields ◽  
Field Amplification ◽  
Kolmogorov Smirnov

We present new analysis of the birth rate of AXPs and SGRS and their associated SNRs. Using Kolmogorov-Smirnov statistics together with parametric fits based on a robust estimator, we find a birth rate of ∼1/(1000 years) for AXPs/SGRs and their associated SNRs. These high rates suggest that all massive stars (greater than ∼(23–32)M⊙) give rise to remnants with magnetar-like fields. Observations indicate a limited fraction of high magnetic fields in these progenitors; thus our study is suggestive of magnetic field amplification. Dynamo mechanisms during the birth of the neutron stars require spin rates much faster than either observations or theory indicate. We propose that massive stars produce neutron stars with normal (∼1012 G) magnetic fields, which are then amplified to1014-1015 G after a delay of hundreds of years. The amplification is speculated to be a consequence of color ferromagnetism and to occur with a delay after the neutron star core reaches quark deconfinement density (i.e., the quark-nova scenario). The delayed amplification allows one to interpret simultaneously the high birth rate and high magnetic fields of AXPs/SGRs and their link to massive stars.

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