Magnetars are compact stars which observationally determined to have very strong surface magnetic fields of the order $10^{14}-10^{15}$G. The centre star can potentially a field several orders magnitude larger. We study effect on mass and shape such star. In general, we assume non-uniform inside varies with density. energy pressure as well metric expanded multipoles in spherical harmonics up quadrupole term. Solving Einstein equations for gravitational potential, one obtains correction terms...

Abstract Matter properties at the intermediate densities are still unknown to us. In this work, we use a neural network approach study matter analyze variation of speed sound and measure trace anomaly considering astrophysical constraints mass–radius measurement 18 neutron stars. Our numerical results show that there is sharp rise in just beyond saturation energy density. It attains peak around 3–4 times density and, after that, decreases. This hints towards appearance new degrees freedom...

The conversion of neutron matter to strange in a star have been studied as two step process. In the first step, nuclear gets converted flavour quark matter. three takes place second step. process is analysed with help equations state and hydrodynamical equations, whereas, process, non-leptonic weak interaction plays main role. Velocities time travel through these fronts compared.

Recent observation of pulsar PSR J1614-2230 with a mass about two solar masses poses severe constraint on the equations state (EOSs) matter describing stars under extreme conditions. Neutron (NSs) can reach limit set by J1614-2230, but having hyperons or quark (QSs) boson condensates, softer EOSs, barely such and are ruled out. QSs pure strange cannot attain high unless effect strong coupling constants color superconductivity considered. In this work I calculate upper for hybrid star (HS)...

ABSTRACT Quantum Chromodynamics predicts phase transition from hadronic matter to quark at high density, which is highly probable in astrophysical systems like binary neutron star mergers. To explore the critical density where such can occur, we performed numerical relativity simulations of mergers with various masses (equal and unequal binaries). We aim understand effect onset on merger dynamics gravitational wave spectra. generated a set equations states by agnostically changing...

In this letter we study the dynamics of a first order phase transition from nucleonic to quark matter in neutron stars. Using standard equations state for these two phases find density range where such is possible. Then transformation star assuming that core formed via spherical shock wave. The thermodynamical conditions are found conservation laws across region. Their dependence on and velocity incoming nuclear studied. It especially violent beginning conversion process when infalling high....

Fluctuation at the neutron star center gives rise to a small deconfined quark core very close center. The density discontinuity quark-hadron boundary initiates shock wave, which propagates outwards of star. has enough energy combust nuclear matter 2-flavor in is not stable and settles 3-flavor weakly interacting timescale. In this paper, we study conversion matter. We set up differential equation convert excess down quarks strange involving weak reaction diffusion quarks. Calculating rate,...

Neural Machine Translation model is a sequence-to-sequence converter based on neural networks. Existing models use recurrent networks to construct both the encoder and decoder modules. In alternative research, were substituted by convolutional for capturing syntactic structure in input sentence decreasing processing time. We incorporate goodness of approaches proposing convolutional-recurrent context information as well sequential from source sentence. Word embedding position performed prior...

In this work we have analyzed the variation of speed sound and trace anomaly inside a neutron star using neural network. We construct family agnostic equation state by maintaining thermodynamic stability, bound with constraints from recent observation stars. The data mass radius serves an input for network obtain as output. shows non-monotonic behaviour trained predicts softer state. stiff at centre intermediate stars massive relatively their centre. untrained however, when train our data;...

Universal relations are important in testing many theories of physics. In the case general relativity, we have celebrated no-hair theorem for black holes. Unfortunately, other compact stars, like neutron stars and white dwarfs, do not such universal relation. However, (and quark stars) recently been found to follow certain universality, I-Love-Q relations. These can provide a greater understanding structural macro properties astrophysical objects with knowledge any one observables. The...

We investigate the General Relativistic (GR) effects on conversion from nuclear to two-flavour quark matter in compact stars, both static as well rotating. find that GR lead qualitative differences rotating indicating inadequacy of non-relativistic (NR) or even Special (SR) treatments for these cases.

Recent results and data suggests that high magnetic field in neutron stars (NS) strongly affects the characteristic (radius, mass) of star. They are even separated as a class known magnetars, for whom surface greater than $10^{14}$ G. In this work we discuss effect such on phase transition NS to quark star (QS). We study from QS including equation state (EoS). The inclusion increases range baryon number density, which flow velocities matter respective finite. helps initiation conversion...

Abstract In this article, we study the combustion of a neutron star to hybrid star. We assume that sudden density fluctuation at center initiates shock discontinuity near This deconfines nuclear matter two-flavor quark matter, initiating front propagates from surface, converting matter. stops some radial point inside star, as wave becomes rather weak. Although stops, simple surface. gravitational-wave signal for such phase transition find has unique strain amplitude 10 −21 . These signals...

We have studied the spin-down induced phase transition in cold, isolated neutron stars this work. After birth, as star slows down, its central density rises and crosses critical of transition, a quark core is seeded inside star. Intermediate mass are more likely to seeding their lifetime at birth. Smaller do not remain throughout life, whereas massive stars, exists center from In intermediate grows further down. The appearance leads sudden change moment inertia evolutionary history, it also...

The estimate of the energy deposition rate (EDR) for neutrino pair annihilation has been carried out. EDR neutrinos coming from equatorial plane a rotating neutron star is calculated along rotation axis using Cook–Shapiro–Teukolsky metric. trajectories and hence emitted disk are affected by redshift due to gravitation. very sensitive value temperature its variation disk. negative effect on EDR; it decreases with increase in rotational velocity.

We solve the Combustion adiabat (CA) or Chapman–Jouget equation to study phase transition (PT) of a neutron star (NS) quark (QS). The hadronic matter and states are used calculate velocities on either side shock front. CA with as an input is solved obtain corresponding values. maximum pressure reflected in retracing path curve. downstream implies towards mass limit transformed QS which different from regular ordinary QS. Further, characterization suggest that PT NS not always feasible centre...

We study the possibility of vector (ρ−) meson condensation in dense matter subject to strong magnetic fields. For this purpose, we adopt a standard relativistic equation state (GM3). find that rho-meson condensates can appear core neutron star as rho mass decreases with density and field. reasonable values parameters, condensate at 4.4 times normal nuclear density. This number guarantees sizeable portion have ρ-condensed phase.

In this work, we have studied the dynamical evolution of shock front in a neutron star. The wave is expected to possess enough strength ignite nuclear matter thereby converting it quark matter. conversion assumed take place at discontinuity. density and pressure discontinuity both spatially temporally as starts near center star moves towards surface. Polytropic equations state which mimics real original are used study such phase transition. Solving relativistic hydrodynamic for spherically...

The concept of quarkyonic matter presents a promising alternative to the conventional models used describe high-density and provides more nuanced detailed understanding properties under extreme conditions that exist in astrophysical bodies. aim this study is showcase effectiveness utilizing model, combination with relativistic mean-field formalism, parameterize equation state at high densities. Through approach, we intend investigate gain insights into various fundamental static neutron...

In this paper, we present the effect of a strong magnetic field in burning neutron star (NS). We have used relativistic magneto-hydrostatic (MHS) conservation equations for studying PT from nuclear matter (NM) to quark (QM). found that shock-induced phase transition (PT) is likely if density core more than three times saturation ([Formula: see text]) density. The conversion process NS (QS) be an exothermic beyond such densities. at center most starts as deflagration process. However, there...

This article studies the maximum mass limit of quark star formed after shock-induced phase transition a cold neutron star. By employing hadronic and equation state that satisfies current bound, we use combustion adiabat conditions to find such limit. The condition results in local or global pressure at an intermediate density range. corresponds for transformed hybrid is usually exothermic if have mass. criteria endothermic depend on whether pressure/energy ratios nuclear are smaller greater...

The Rankine-Hugoniot condition has been solved to study phase transition in an astrophysical scenario mainly the case of from a neutron star (NS) quark (QS). equations state and temperature play huge role determining nature front propagation, which brings about NS. shock jump conditions can be analytically, but situation changes drastically by inclusion magnetic field. High fields, are always associated with NS structure evolution So, field introduced de Hoffmann-Teller frame. modified...

Hadronic to quark matter phase transition may occur inside neutron stars (NS) having central densities of the order 3-10 times normal nuclear saturation density (n 0 ).The is expected be a two-step process; from hadronic 2-flavour and two-flavour β equilibrated charge neutral three-flavour matter.In this paper we concentrate on first step process solve relativistic hydrodynamic equations for conversion front in presence high magnetic field.Lorentz force due field included energy momentum...