R-mode oscillations of rapidly rotating Newtonian stars: A new numerical scheme and its application to the spin evolution of neutron stars

2000 ◽  
Vol 62 (8) ◽  
Author(s):  
Shigeyuki Karino ◽  
Shin’ichirou Yoshida ◽  
Shijun Yoshida ◽  
Yoshiharu Eriguchi
Keyword(s):  
Neutron Stars ◽  
Numerical Scheme ◽  
Spin Evolution

scholarly journals Pulsars & Magnetars

2008 ◽  
Vol 4 (S259) ◽  
pp. 485-492 ◽  
Author(s):  
Michael Kramer
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Evolutionary Sequence ◽  
Radio Pulsars ◽  
Observable Universe ◽  
Spin Evolution ◽  
Field Strengths

AbstractThe largest magnetic field encountered in the observable Universe can be found in neutron stars, in particular in radio pulsars and magnetars. While recent discoveries have slowly started to blur the distinction between these two classes of highly magnetized neutron stars, it is possible that both types of sources are linked via an evolutionary sequence. Indications for this to be the case are obtained from observations of the spin-evolution of pulsars. It is found that most young pulsars are heading across the top of the main distribution of radio pulsars in the P–Ṗ-diagram, suggesting that at least a sub-class of young pulsars may evolve into objects with magnetar-like magnetic field strengths. Part of this evolutionary sequence could be represented by RRATs which appear to share at least in parts properties with both pulsars and magnetars.

scholarly journals THE R-MODE INSTABILITY IN ROTATING NEUTRON STARS

2001 ◽  
Vol 10 (04) ◽  
pp. 381-441 ◽  
Author(s):  
NILS ANDERSSON ◽  
KOSTAS D. KOKKOTAS
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Binary Systems ◽  
Current Understanding ◽  
Mode Instability ◽  
Spin Evolution ◽  
Astrophysical Significance

In this review we summarize the current understanding of the gravitational-wave driven instability associated with the so-called r-modes in rotating neutron stars. We discuss the nature of the r-modes, the detailed mechanics of the instability and its potential astrophysical significance. In particular we discuss results regarding the spin-evolution of nascent neutron stars, the detectability of r-mode gravitational waves and mechanisms limiting the spin-rate of accreting neutron stars in binary systems.

scholarly journals Braking indices and spin evolution: something is loose inside neutron stars

2017 ◽  
Vol 13 (S337) ◽  
pp. 221-224
Author(s):  
Cristóbal M. Espinoza
Keyword(s):  
Neutron Stars ◽  
Loosely Coupled ◽  
Spin Evolution

AbstractBraking indices are used to describe the evolution of pulsars rotation, and can offer insights into the braking mechanism that dominates the slow down. Here we discuss the main difficulties associated with measuring braking indices and the complexity of interpreting these measurements. Considering recent braking index measurements on pulsars with large and regular glitches, we comment on the significant effects that the loosely coupled superfluid inside pulsars might have on their spin evolution.

scholarly journals Spin evolution of neutron stars in wind-fed high-mass X-ray binaries

2020 ◽  
Vol 72 (6) ◽  
Author(s):  
Shigeyuki Karino
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Neutron Stars ◽  
Wind Velocity ◽  
High Mass ◽  
Quasi Equilibrium ◽  
Pulse Period ◽  
X Ray ◽  
Spin Evolution ◽  
The Magnetic Field

Abstract The observed X-ray pulse period of OB-type high-mass X-ray binary (HMXB) pulsars is typically longer than 100 seconds. It is considered that the interaction between the strong magnetic field of a neutron star and the wind matter could cause such a long pulse period. In this study, we follow the spin evolution of neutron stars, taking into account the interaction between the magnetic field and wind matter. In this line, as new challenges, we solve the evolution of the magnetic field of the neutron star at the same time, and additionally we focus on the effects of the wind properties of the donor. As a result, evolutionary tracks were obtained in which the neutron star spends some duration in the ejector phase after birth, then rapidly spins down, becomes quasi-equilibrium, and gradually spins up. Such evolution is similar to previous studies, but we found that its dominant physics depends on the velocity of the donor wind. When the wind velocity is fast, the spin-down occurs due to magnetic inhibition, while the classical propeller effect and settling accretion shell causes rapid spin-down in the slow wind accretion. Since the wind velocity of the donor could depend on the irradiated X-ray luminosity, the spin evolution track of the neutron star in a wind-fed HMXB could be more complicated than considered.

scholarly journals EVIDENCE FOR MAGNETO-LEVITATION ACCRETION IN LONG-PERIOD X-RAY PULSARS

2014 ◽  
Vol 28 ◽  
pp. 1460187 ◽  
Author(s):  
NAZAR IKHSANOV ◽  
NINA BESKROVNAYA ◽  
YURY LIKH
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Disk Accretion ◽  
X Ray ◽  
Accretion Flow ◽  
Long Period ◽  
Intrinsic Magnetic Field ◽  
Spin Evolution ◽  
Accretion Model

Study of observed spin evolution of long-period X-ray pulsars challenges quasi-spherical and Keplerian disk accretion scenarios. It suggests that the magnetospheric radius of the neutron stars is substantially smaller than Alfvén radius and the spin-down torque applied to the star from accreting material significantly exceeds the value predicted by the theory. We show that these problems can be avoided if the fossil magnetic field of the accretion flow itself is incorporated into the accretion model. The initially spherical flow in this case decelerates by its own magnetic field and converts into a non-Keplerian disk (magnetic slab) in which the material is confined by its intrinsic magnetic field ("levitates") and slowly moves towards the star on a diffusion timescale. Parameters of pulsars expected within this magneto-levitation accretion scenario are evaluated.

scholarly journals Hyperon softening of the EOS of dense matter and the spin evolution of isolated neutron stars

2004 ◽  
Vol 416 (3) ◽  
pp. 1013-1022 ◽  
Author(s):  
J. L. Zdunik ◽  
P. Haensel ◽  
E. Gourgoulhon ◽  
M. Bejger
Keyword(s):  
Neutron Stars ◽  
Dense Matter ◽  
Spin Evolution

Spin Evolution of Neutron Stars in OB/X-ray Binaries

2004 ◽  
Vol 4 (4) ◽  
pp. 320-334 ◽  
Author(s):  
Fan Zhang ◽  
Xiang-Dong Li ◽  
Zhen-Ru Wang
Keyword(s):  
Neutron Stars ◽  
X Ray ◽  
Spin Evolution ◽  
X Ray Binaries
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