scholarly journals Quark deconfinement in high-mass neutron stars

2014 ◽  
Vol 89 (1) ◽  
Author(s):  
M. Orsaria ◽  
H. Rodrigues ◽  
F. Weber ◽  
G. A. Contrera
Keyword(s):  
Neutron Stars ◽  
High Mass ◽  
Quark Deconfinement

scholarly journals High-Mass X-ray Binaries: progenitors of double compact objects

2018 ◽  
Vol 14 (S346) ◽  
pp. 1-13
Author(s):  
Edward P. J. van den Heuvel
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Compact Objects ◽  
High Mass ◽  
X Ray ◽  
Future Evolution ◽  
Short Period ◽  
Orbital Periods ◽  
X Ray Binaries

AbstractA summary is given of the present state of our knowledge of High-Mass X-ray Binaries (HMXBs), their formation and expected future evolution. Among the HMXB-systems that contain neutron stars, only those that have orbital periods upwards of one year will survive the Common-Envelope (CE) evolution that follows the HMXB phase. These systems may produce close double neutron stars with eccentric orbits. The HMXBs that contain black holes do not necessarily evolve into a CE phase. Systems with relatively short orbital periods will evolve by stable Roche-lobe overflow to short-period Wolf-Rayet (WR) X-ray binaries containing a black hole. Two other ways for the formation of WR X-ray binaries with black holes are identified: CE-evolution of wide HMXBs and homogeneous evolution of very close systems. In all three cases, the final product of the WR X-ray binary will be a double black hole or a black hole neutron star binary.

scholarly journals Signal of quark deconfinement in thermal evolution neutron stars with deconfinement heating

New Astronomy ◽  
2010 ◽  
Vol 15 (6) ◽  
pp. 515-519 ◽  
Author(s):  
Miao Kang ◽  
Xiao-Dong Wang ◽  
Xiao-Ping Zheng
Keyword(s):  
Neutron Stars ◽  
Thermal Evolution ◽  
Quark Deconfinement

scholarly journals MASSES OF NEUTRON STARS IN HIGH-MASS X-RAY BINARIES WITH OPTICAL ASTROMETRY

2010 ◽  
Vol 719 (1) ◽  
pp. 958-965 ◽  
Author(s):  
John A. Tomsick ◽  
Matthew W. Muterspaugh
Keyword(s):  
Neutron Stars ◽  
High Mass ◽  
X Ray ◽  
X Ray Binaries

Neutron Star Matter and Neutron Star Models

1974 ◽  
Vol 29 (6) ◽  
pp. 933-946
Author(s):  
H. Heintzmann ◽  
W. Hillebrandt ◽  
M. F. El Eid ◽  
E. R. Hilf
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
High Mass ◽  
Mass Limit ◽  
Neutron Star Matter ◽  
Density Region ◽  
Star Models ◽  
Boson Exchange ◽  
Realistic Interaction ◽  
General Relativistic

Various methods to study the ground state of neutron star matter are compared and the corresponding neutron star models are contrasted with each other. In the low density region ρ < 1014gr cm-3 the nuclear gas is treated here by means of a Thomas Fermi method and the nuclei are described by the droplet model of Myers and Swiatecki. For ρ > 1014 gr cm-3 both standard Brueckner theory with more realistic interaction (one-boson-exchange) potentials and the semiphenomenological theory of Fermi liquids (together with the standard Reid softcore potential) are applied to neutron star matter. It is shown that while the high mass limit of neutron stars is hardly affected, some properties of lowmass neutron stars such as their binding depend sensitively on these refinements. Various tentative (but unreliable) extensions of the equation of state into high density regime ρ > 1015 gr cm-3 are investigated and it is shown that the mass limit for heavy neutron stars lies around 2.5 solar masses. It is further shown that a third family of stable (hyperon) stars is not forbidden by general relativistic arguments if there is a phase transition at high densities.

scholarly journals COOLING AND DETECTABILITY OF NEUTRON STARS

1966 ◽  
Vol 44 (8) ◽  
pp. 1863-1894 ◽  
Author(s):  
Sachiko Tsuruta ◽  
A. G. W. Cameron
Keyword(s):  
Neutron Stars ◽  
Surface Composition ◽  
High Mass ◽  
Nuclear Potential ◽  
Surface Layers ◽  
Stellar Radius ◽  
Cooling Behavior ◽  
Low Mass ◽  
Fast Cooling ◽  
Bremsstrahlung Process

Surface properties, temperature effects, cooling behavior, and observability of neutron stars have been studied. For this purpose, the opacity of the surface layers is calculated both for a pure iron and a pure magnesium composition. It is found that the nondegenerate layers are only a few meters thick and in no case exceed 1% of the stellar radius. The star cools mainly through neutrino emission when [Formula: see text], but at lower temperatures the cooling is primarily through electromagnetic radiation. The neutrino cooling mechanisms included were the neutrino plasma process, the URCA process, and the neutrino bremsstrahlung process. The cooling behavior is quite complicated, with the rate of cooling generally depending on mass, nuclear potential, and surface composition, among which the dependence on mass is the most significant. It will be hard to observe low-mass neutron stars because of fast cooling rates. However, medium-and high-mass stars should still have temperatures exceeding about 2 × 106 °K on the surface for times of the order of 103 to 105 years. Hence, it should not be impossible to observe massive neutron stars relatively close to us, if there is no X-ray emission of larger flux coming from the surrounding region.

scholarly journals Exploration of spin-down rate of neutron stars in high-mass X-ray binaries

2016 ◽  
Vol 457 (4) ◽  
pp. 3889-3895 ◽  
Author(s):  
Hai-Lang Dai ◽  
Xi-Wei Liu ◽  
Xiang-Dong Li
Keyword(s):  
Neutron Stars ◽  
High Mass ◽  
X Ray ◽  
X Ray Binaries

scholarly journals Accreting Neutron Stars

1987 ◽  
Vol 125 ◽  
pp. 135-148
Author(s):  
N.E. White
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Neutron Stars ◽  
Magnetic Field Strength ◽  
Spectral Properties ◽  
High Mass ◽  
X Ray ◽  
Temporal Properties ◽  
Low Mass ◽  
X Ray Binaries

This paper reviews accreting neutron stars in X-ray binaries, with particular emphasis on how variations in magnetic field strength may be responsible for explaining the spectral and temporal properties observed from the various systems. This includes a review of X-ray pulsars in both low and high mass systems, and a discussion of the spectral properties of the low mass X-ray binaries.

scholarly journals Supergiant Fast X-ray Transients uncovered by the EXTraS project: flares reveal the development of magnetospheric instability in accreting neutron stars

2019 ◽  
Vol 487 (1) ◽  
pp. 420-434
Author(s):  
Lara Sidoli ◽  
Konstantin A Postnov ◽  
Andrea Belfiore ◽  
Martino Marelli ◽  
David Salvetti ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Large Range ◽  
Accretion Rate ◽  
Light Curves ◽  
High Mass ◽  
Time Interval ◽  
X Ray ◽  
Rayleigh Taylor Instability ◽  
X Ray Binaries ◽  
Peak Luminosity

ABSTRACT The low luminosity, X-ray flaring activity, of the sub-class of high-mass X-ray binaries called Supergiant Fast X-ray Transients, has been investigated using XMM–Newton public observations, taking advantage of the products made publicly available by the EXTraS project. One of the goals of EXTraS was to extract from the XMM–Newton public archive information on the aperiodic variability of all sources observed in the soft X-ray range with EPIC (0.2–12 keV). Adopting a Bayesian block decomposition of the X-ray light curves of a sample of SFXTs, we picked out 144 X-ray flares, covering a large range of soft X-ray luminosities (1032–1036 erg s−1). We measured temporal quantities, like the rise time to and the decay time from the peak of the flares, their duration and the time interval between adjacent flares. We also estimated the peak luminosity, average accretion rate, and energy release in the flares. The observed soft X-ray properties of low-luminosity flaring activity from SFXTs is in qualitative agreement with what is expected by the application of the Rayleigh–Taylor instability model in accreting plasma near the neutron star magnetosphere. In the case of rapidly rotating neutron stars, sporadic accretion from temporary discs cannot be excluded.

scholarly journals STRANGENESS IN NEUTRON STARS

2007 ◽  
Vol 16 (02n03) ◽  
pp. 231-245 ◽  
Author(s):  
FRIDOLIN WEBER ◽  
ALEXANDER HO ◽  
RODRIGO P. NEGREIROS ◽  
PHILIP ROSENFIELD
Keyword(s):  
Neutron Stars ◽  
Quark Matter ◽  
Strange Quark ◽  
Baryon Number ◽  
Heavy Ion ◽  
Strange Quark Matter ◽  
Relativistic Heavy Ion Collision ◽  
Quark Deconfinement ◽  
Ion Collision ◽  
High Pressure Environment

It is generally agreed on that the tremendous densities reached in the centers of neutron stars provide a high-pressure environment in which several intriguing particles processes may compete with each other. These range from the generation of hyperons to quark deconfinement to the formation of kaon condensates and H-matter. There are theoretical suggestions of even more exotic processes inside neutron stars, such as the formation of absolutely stable strange quark matter. In the latter event, neutron stars would be largely composed of strange quark matter possibly enveloped in a thin nuclear crust. This paper gives a brief overview of these striking physical possibilities with an emphasis on the role played by strangeness in neutron star matter, which constitutes compressed baryonic matter at ultra-high baryon number density but low temperature which is not accessible to relativistic heavy ion collision experiments.

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