scholarly journals Roto-Chemical Heating with Fall-Back Disk Accretion in the Neutron Stars Containing Quark Matter

Universe ◽  
2020 ◽  
Vol 6 (5) ◽  
pp. 62
Author(s):  
Wei Wei ◽  
Xin-Yu Xu ◽  
Kai-Tuo Wang ◽  
Xiao-Hang Ma
Keyword(s):  
Surface Temperature ◽  
Neutron Stars ◽  
Chemical Evolution ◽  
Quark Matter ◽  
Accretion Rate ◽  
Thermal Evolution ◽  
Sudden Change ◽  
Heating Effect ◽  
Chemical Balance ◽  
Chemical Heating

Probing quark matter is one of the important tasks in the studies of neutron stars (NS). Some works explicitly consider the existence of quark matter in the appearance of hybrid star (HS) or pure quark star (QS). In the present work, we study the roto-chemical heating with accretion in HS and QS, and compare their chemical evolution and cooling features with pure NS. Different from HS and NS, there are two jumps in the chemical evolution of QS, which results from the fast direct Urca (Durca) reaction causing the fast recovery to chemical balance. However, the sudden change in the chemical evolution doesn’t provide an obvious heating effect in the thermal evolution. Differently, the roto-chemical heating effect appears both in the accretion phase and spin-down phase of the HS, and the heating platform in the accretion phase relies on the accretion rate. Larger accretion rate results in larger chemical deviation, higher and longer heating platform, and earlier appearance of the heating effect. Interestingly, with the disappearance of the heating effect in the accretion phase, the surface temperature drops fast, which is another possibility of the rapid cooling trend of the NS in Cas A. Furthermore, the surface temperature of the QS is obviously lower than the HS and NS, which is a latent candidate for the explanation of the old classical pulsar J2144-3933 with the lowest known surface temperature.

scholarly journals Mutual influence of magnetic field decay and thermal evolution of rotational neutron stars

2012 ◽  
Vol 8 (S291) ◽  
pp. 586-588
Author(s):  
Xia Zhou ◽  
Miao Kang ◽  
Na Wang
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Mutual Influence ◽  
Thermal Evolution ◽  
Chemical Heating ◽  
Field Decay ◽  
The Magnetic Field

AbstractThe effect of magnetic field decay on the chemical heating and thermal evolution of neutron stars is discussed. Our main goal is to study how chemical heating mechanisms and thermal evolution are changed by field decay and how magnetic field decay is modified by the thermal evolution. We show that the effect of chemical heating is suppressed by the star spin-down through decaying magnetic field at a later stage; magnetic field decay is delayed significantly relative to stars cooling without heating mechanisms; compared to typical chemical heating, the decay of the magnetic field can even cause the temperature to turn down at a later stage.

scholarly journals Revisiting the thermal relaxation of neutron stars

2020 ◽  
Vol 642 ◽  
pp. A42
Author(s):  
Thiago Sales ◽  
Odilon Lourenço ◽  
Mariana Dutra ◽  
Rodrigo Negreiros
Keyword(s):  
Relaxation Time ◽  
Surface Temperature ◽  
Neutron Stars ◽  
Equations Of State ◽  
Thermal Evolution ◽  
Relaxation Times ◽  
Thermal Relaxation ◽  
Neutrino Production ◽  
Fast Cooling ◽  
Late Relaxation Time

In this work, we revisit the thermal relaxation process for neutron stars. Such a process is associated with the thermal coupling between the core and the crust of neutron stars. The thermal relaxation, which takes place at around 10–100 years, is manifested as a sudden drop in the star’s surface temperature. Such a drop is smooth for slowly cooling objects and very sharp for fast-cooling ones. In our study, we focused particularly on the cooling of neutron stars whose mass is slightly greater than the value above which the direct Urca (DU) process sets in. Considering different mechanisms for neutrino production in each region of the star, and working with equations of state with different properties, we solved the thermal evolution equation and calculated the thermal relaxation time for an ample range of neutron star masses. By performing a comprehensive study of neutron stars just above the onset of the DU process, we show that stars under these conditions exhibit a peculiar thermal relaxation behavior. We demonstrate that such stars exhibit an abnormally late relaxation time, characterized by a second drop in its surface temperature taking place a later age. We qualified such behavior by showing that it is associated with limited spatial distribution of the DU process in such stars. We show that as the star’s mass increases, the DU region also grows, and the star exhibits the expected behavior of fast-cooling stars. Finally, we show that one can expect high relaxation times for stars in which the DU process takes place in a radius no larger than 3 km.

scholarly journals Cooling theory faced with old warm neutron stars: role of non-equilibrium processes with proton and neutron gaps

2020 ◽  
Vol 492 (4) ◽  
pp. 5508-5523 ◽  
Author(s):  
Keisuke Yanagi ◽  
Natsumi Nagata ◽  
Koichi Hamaguchi
Keyword(s):  
Neutron Star ◽  
Surface Temperature ◽  
Neutron Stars ◽  
Initial Period ◽  
Late Time ◽  
Heating Effect ◽  
Surface Temperatures ◽  
Triplet Pairing ◽  
Set Up ◽  
Non Equilibrium

ABSTRACT Recent observations have found several candidates for old warm neutron stars whose surface temperatures are above the prediction of the standard neutron star cooling scenario, and, thus, require some heating mechanism. Motivated by these observations, we study the non-equilibrium beta process in the minimal cooling scenario of neutron stars, which inevitably occurs in pulsars. This out-of-equilibrium process yields the late-time heating in the core of a neutron star, called the rotochemical heating, and significantly changes the time evolution of the neutron star surface temperature. To perform a realistic analysis of this heating effect, we include the proton-singlet- and neutron-triplet-pairing gaps simultaneously in the calculation of the rate and emissivity of this process, where the dependence of these pairing gaps on the nucleon density is also taken into account. We then compare the predicted surface temperature of neutron stars with the latest observational data. We show that the simultaneous inclusion of both proton and neutron gaps is advantageous for the explanation of the old warm neutron stars since it enhances the heating effect. It is then found that the observed surface temperatures of the old warm millisecond pulsars, J2124−3358 and J0437−4715, are explained for various choices of nucleon gap models. The same set-up is compatible with the observed temperatures of ordinary pulsars, including old warm ones, J0108−1431 and B0950+08, by choosing the initial rotational period of each neutron star accordingly. In particular, the upper limit on the surface temperature of J2144−3933 can be satisfied if its initial period is $\gtrsim 10\, \mathrm{ms}$.

FROM CRUST TO CORE: A BRIEF REVIEW OF QUARK MATTER IN NEUTRON STARS

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1427-1436 ◽  
Author(s):  
F. WEBER ◽  
O. HAMIL ◽  
K. MIMURA ◽  
R. NEGREIROS
Keyword(s):  
Neutron Stars ◽  
Electric Fields ◽  
Quark Matter ◽  
Strange Quark ◽  
Thermal Evolution ◽  
Reaction Rates ◽  
Strange Quark Matter ◽  
Compact Objects ◽  
Compact Stars ◽  
The Impact

This paper provides a short overview of the multifaceted, possible role of quark matter for compact stars (neutron stars and strange quark matter stars). We began with a variational investigation of the maximum possible energy densities in the cores of neutron stars. This is followed by a brief discussion of the possible existence of quark matter in the cores of neutron stars and how such matter could manifest itself in neutron star observables. The possible presence of color superconducting strange quark matter nuggets in the crusts of neutron stars is reviewed next, and their impact on the pycnonuclear reaction rates in the crusts of neutron stars is discussed. The second part of the paper discusses the impact of ultra-strong electric fields on the bulk properties of strange quark matter stars and presents results of a preliminary study that models the thermal evolution of radio-quiet, X-ray bright, central compact objects (CCOs).

Joule Heating and the Thermal Evolution of Old Neutron Stars

1998 ◽  
Vol 503 (1) ◽  
pp. 368-373 ◽  
Author(s):  
Juan A. Miralles ◽  
Vadim Urpin ◽  
Denis Konenkov
Keyword(s):  
Neutron Stars ◽  
Joule Heating ◽  
Thermal Evolution

scholarly journals A full relativistic thin disc - the physics of the plunging region and the value of the stress at the ISCO

2021 ◽  
Author(s):  
William J Potter
Keyword(s):  
Black Hole ◽  
Surface Temperature ◽  
Accretion Rate ◽  
Speed Of Light ◽  
Thin Disc ◽  
Stable Circular Orbit ◽  
Stress Surface ◽  
Innermost Stable Circular Orbit ◽  
Turbulent Heating ◽  
Local Surface Temperature

Abstract The widely used Novikov-Thorne relativistic thin disc equations are only valid down to the radius of the innermost-stable circular orbit (ISCO). This leads to an undetermined boundary condition at the ISCO, known as the inner stress of the disc, which sets the luminosity of the disc at the ISCO and introduces considerable ambiguity in accurately determining the mass, spin and accretion rate of black holes from observed spectra. We resolve this ambiguity by self-consistently extending the relativistic disc solution through the ISCO to the black hole horizon by calculating the inspiral of an average disc particle subject to turbulent disc forces, using a new particle-in-disc technique. Traditionally it has been assumed that the stress at the ISCO is zero, with material plunging approximately radially into the black hole at close to the speed of light. We demonstrate that in fact the inspiral is less severe, with several (∼4 − 17) orbits completed before the horizon. This leads to a small non-zero stress and luminosity at and inside the ISCO, with a local surface temperature at the ISCO between ∼0.15 − 0.3 times the maximum surface temperature of the disc, in the case where no dynamically important net magnetic field is present. For a range of disc parameters we calculate the value of the inner stress/surface temperature, which is required when fitting relativistic thin disc models to observations. We resolve a problem in relativistic slim disc models in which turbulent heating becomes inaccurate and falls to zero inside the plunging region.

scholarly journals The relativistic mass accretion rate for accretion disk in the equatorial of rapidly rotating neutron stars

2021 ◽  
Vol 1869 (1) ◽  
pp. 012156
Author(s):  
A Yasrina ◽  
N Widianingrum ◽  
N S Risdianto ◽  
D Andra ◽  
N A Pramono ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Accretion Disk ◽  
Accretion Rate ◽  
Mass Accretion Rate ◽  
Relativistic Mass

scholarly journals Nuclear equation of state and neutron star cooling

2017 ◽  
Vol 26 (04) ◽  
pp. 1750015 ◽  
Author(s):  
Yeunhwan Lim ◽  
Chang Ho Hyun ◽  
Chang-Hwan Lee
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Thermal Evolution ◽  
Observation Data ◽  
Nuclear Equation Of State ◽  
The Core ◽  
Dense Nuclear Matter ◽  
Nuclear Models

In this paper, we investigate the cooling of neutron stars with relativistic and nonrelativistic models of dense nuclear matter. We focus on the effects of uncertainties originated from the nuclear models, the composition of elements in the envelope region, and the formation of superfluidity in the core and the crust of neutron stars. Discovery of [Formula: see text] neutron stars PSR J1614−2230 and PSR J0343[Formula: see text]0432 has triggered the revival of stiff nuclear equation of state at high densities. In the meantime, observation of a neutron star in Cassiopeia A for more than 10 years has provided us with very accurate data for the thermal evolution of neutron stars. Both mass and temperature of neutron stars depend critically on the equation of state of nuclear matter, so we first search for nuclear models that satisfy the constraints from mass and temperature simultaneously within a reasonable range. With selected models, we explore the effects of element composition in the envelope region, and the existence of superfluidity in the core and the crust of neutron stars. Due to uncertainty in the composition of particles in the envelope region, we obtain a range of cooling curves that can cover substantial region of observation data.

Quark matter in neutron stars

2004 ◽  
Vol 19 (S1) ◽  
pp. 189-196
Author(s):  
Marcello Baldo
Keyword(s):  
Neutron Stars ◽  
Quark Matter

scholarly journals Converting neutron stars into strange stars: Instanton model

2014 ◽  
Vol 23 (09) ◽  
pp. 1450078
Author(s):  
Victor Ts. Gurovich ◽  
Leonid G. Fel
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Detonation Wave ◽  
Neutron Stars ◽  
Quark Matter ◽  
Quantum Fluctuation ◽  
The Self ◽  
Quantum Field ◽  
Spherical Detonation ◽  
Self Similar

We calculate the quasiclassical probability to emerge the quantum fluctuation which gives rise to the quark-matter drop with interface propagating as the self-similar spherical detonation wave (DN) in the ambient nuclear matter. For this purpose, we make use of instanton method which is known in the quantum field theory.

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