scholarly journals Spin Evolution of the Progenitors of Binary and Millisecond Pulsars

1996 ◽  
Vol 165 ◽  
pp. 57-64
Author(s):  
Pranab Ghosh
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Binary System ◽  
Neutron Stars ◽  
High Magnetic Field ◽  
Evolutionary History ◽  
Millisecond Pulsars ◽  
History Of ◽  
Low Magnetic Field ◽  
Fast Rotating

In this symposium, I have been given the task of summarizing our current understanding of the evolutionary history of spin periods of the neutron stars that we now see as binary and millisecond pulsars, i.e., recycled pulsars. We believe that a newborn, fast-spinning neutron star (with a rather high magnetic field ∼1011–1013 G) in a binary system first operates as a spin-powered pulsar, subsequently as an accretion-powered pulsar when accretion begins after the pulsar has been spun down adequately, and finally as a spin-powered pulsar for the second time after having been recycled to become a very fast-rotating neutron star (with a rather low magnetic field ∼108–1011 G) (see Ghosh 1994a, b, hereafter G94a, b).

scholarly journals Recycled pulsars with multipolar magnetospheres from accretion-induced magnetic burial

2020 ◽  
Vol 499 (3) ◽  
pp. 3243-3254
Author(s):  
A G Suvorov ◽  
A Melatos
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Field Line ◽  
Dipole Field ◽  
Multipole Moments ◽  
Millisecond Pulsars ◽  
The Magnetic Field ◽  
Field Strengths

ABSTRACT Many millisecond pulsars are thought to be old neutron stars spun up (‘recycled’) during an earlier accretion phase. They typically have relatively weak (≲109 G) dipole field strengths, consistent with accretion-induced magnetic burial. Recent data from the Neutron Star Interior Composition Explorer indicate that hotspots atop the recycled pulsar PSR J0030–0451 are not antipodal, so that the magnetic field cannot be that of a centred dipole. In this paper it is shown that multipolarity is naturally expected in the burial scenario because of equatorial field line compression. Grad–Shafranov equilibria are constructed to show how magnetic multipole moments can be calculated in terms of various properties, such as the amount of accreted mass and the crustal equation of state.

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 Detecting UV Radiation from Nearby Pulsars with the Hubble Space Telescope

1992 ◽  
Vol 128 ◽  
pp. 220-221
Author(s):  
George G. Pavlov
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Thermal Radiation ◽  
Neutron Stars ◽  
Hubble Space Telescope ◽  
Thermal Evolution ◽  
The Sun ◽  
Space Telescope ◽  
Additional Constraints ◽  
Relativistic Particles

AbstractEven old (106 to 107 yr) pulsars within a few hundred parsecs of the Sun should give UV and optical fluxes via thermal radiation or radiation from relativistic particles. The surface temperature of a neutron star depends on its mass, radius, magnetic field, and internal composition (existence of pion condensate, superfluidity of nucléons, etc.). If the temperature exceeds ~2x104 K, the thermal radiation can be detected by the Hubble Space Telescope. An analysis of the results will allow one to study the thermal evolution and inner structure of neutron stars in order to obtain additional constraints on pulsar models.

scholarly journals Estimation of Electrical Conductivity and Magnetization Parameter of Neutron Star Crusts and Applied to the High-Braking-Index Pulsar PSR J1640-4631

Universe ◽  
2020 ◽  
Vol 6 (5) ◽  
pp. 63
Author(s):  
Hui Wang ◽  
Zhi-Fu Gao ◽  
Huan-Yu Jia ◽  
Na Wang ◽  
Xiang-Dong Li
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Neutron Stars ◽  
General Expression ◽  
Equations Of State ◽  
Rotation Period ◽  
Ohmic Dissipation ◽  
Hartree Fock ◽  
Induction Equation ◽  
The Magnetic Field

Young pulsars are thought to be highly magnetized neutron stars (NSs). The crustal magnetic field of a NS usually decays at different timescales in the forms of Hall drift and Ohmic dissipation. The magnetization parameter ω B τ is defined as the ratio of the Ohmic timescale τ O h m to the Hall drift timescale τ H a l l . During the first several million years, the inner temperature of the newly born neutron star cools from T = 10 9 K to T = 1.0 × 10 8 K, and the crustal conductivity increases by three orders of magnitude. In this work, we adopt a unified equations of state for cold non-accreting neutron stars with the Hartree–Fock–Bogoliubov method, developed by Pearson et al. (2018), and choose two fiducial dipole magnetic fields of B = 1.0 × 10 13 G and B = 1.0 × 10 14 G, four different temperatures, T, and two different impurity concentration parameters, Q, and then calculate the conductivity of the inner crust of NSs and give a general expression of magnetization parameter for young pulsars: ω B τ ≃ ( 1 − 50 ) B 0 / ( 10 13 G) by using numerical simulations. It was found when B ≤ 10 15 G, due to the quantum effects, the conductivity increases slightly with the increase in the magnetic field, the enhanced magnetic field has a small effect on the matter in the low-density regions of the crust, and almost has no influence the matter in the high-density regions. Then, we apply the general expression of the magnetization parameter to the high braking-index pulsar PSR J1640-4631. By combining the observed arrival time parameters of PSR J1640-4631 with the magnetic induction equation, we estimated the initial rotation period P 0 , the initial dipole magnetic field B 0 , the Ohm dissipation timescale τ O h m and Hall drift timescale τ H a l l . We model the magnetic field evolution and the braking-index evolution of the pulsar and compare the results with its observations. It is expected that the results of this paper can be applied to more young pulsars.

scholarly journals X-ray Emission Characteristics of Pulsars

2000 ◽  
Vol 195 ◽  
pp. 49-60
Author(s):  
W. Becker
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Emission Characteristics ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Emission Properties ◽  
Important Progress

Recent X-ray observatories such as ROSAT, ASCA, RXTE, BeppoSAX, and Chandra have achieved important progress in neutron star and pulsar astronomy. The identification of Geminga as a rotation-powered pulsar, the discovery of X-ray emission from millisecond pulsars, and the identification of cooling neutron stars are only a few of the fascinating results. In the following, I will give a brief review on the X-ray emission properties of rotation-powered pulsars and their wind nebulae.

scholarly journals Partially ionized layers of accreted envelopes of weakly and strongly magnetized neutron stars

2000 ◽  
Vol 177 ◽  
pp. 619-620 ◽  
Author(s):  
Alexander Potekhin ◽  
Gilles Chabrier ◽  
Yuri Shibanov
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Strong Field ◽  
Ionization Degree ◽  
Occupation Numbers ◽  
Partially Ionized

AbstractWe study equilibrium properties of partially ionized hydrogen atmospheres and subphotospheric layers of weakly (with magnetic fieldB≪ 109G) and strongly (B≫ 1010G) magnetized neutron stars. In both weak- and strong-field cases, the ionization degree, atomic occupation numbers, and equation of state are calculated. These results are used to calculate opacities of neutron-star atmospheres.

scholarly journals On isolated millisecond pulsars formed by the coalescence of neutron stars and massive white dwarfs

2019 ◽  
Vol 36 ◽  
Author(s):  
Shengnan Sun ◽  
Lin Li ◽  
Helei Liu ◽  
Guoliang Lü ◽  
Zhaojun Wang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Neutron Star ◽  
Neutron Stars ◽  
White Dwarf ◽  
White Dwarfs ◽  
Birth Rate ◽  
Population Synthesis ◽  
Solar Mass ◽  
Millisecond Pulsars ◽  
The Stability

Abstract This paper uses population synthesis to investigate the possible origin of isolated millisecond pulsars as born from the coalescence of a neutron star and a white dwarf. Results show that the galactic birth rate of isolated millisecond pulsars is likely to lie between 5.8×10−5 yr−1 and 2.0×10−4 yr−1, depending on critical variables, such as the stability of mass transfer via the Roche lobe and the value of kick velocity. In addition to this, this paper estimates that the solar mass of isolated millisecond pulsars can range from 1.5 and 2.0 Mʘ, making them more massive than other ‘normal’ pulsars. Finally, the majority of isolated millisecond pulsars in our simulations have spin periods ranging from several to 20 ms, which is consistent with previous observations.

scholarly journals Very young neutron stars and millisecond pulsars: the role of the accretion

2012 ◽  
Vol 8 (S290) ◽  
pp. 231-232
Author(s):  
Alexander F. Kholtygin ◽  
Andrei P. Igoshev
Keyword(s):  
Magnetic Fields ◽  
Neutron Stars ◽  
Binary Systems ◽  
Compact Objects ◽  
Millisecond Pulsars ◽  
Know How ◽  
Central Compact Objects ◽  
Low Magnetic Field ◽  
Age Determinations

AbstractWe consider the evolution of the very young neutron stars (NS) with moderate and low magnetic field values around 1E8 G to know how large is the share of the these objects among the those attributed as the millisecond pulsars (MSP). To exclude the contamination of accreted NS and young NS with moderate magnetic fields we study the observational evidences of the accretion on NS in the binary systems and different methods of age determinations. It was concluded that only central compact objects are appropriate candidates for NSs with small initial magnetic fields.

scholarly journals Magnetized Neutron Stars

2017 ◽  
Vol 45 ◽  
pp. 1760032
Author(s):  
Gibran H. de Souza ◽  
Ernesto Kemp ◽  
Cecilia Chirenti
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Neutron Stars ◽  
Numerical Solutions ◽  
Internal Magnetic Field ◽  
Shafranov Equation ◽  
Field Lines

In this work we show the results for numerical solutions of the relativistic Grad-Shafranov equation for a typical neutron star with 1.4 solar masses. We have studied the internal magnetic field considering both the poloidal and toroidal components, as well as the behavior of the field lines parametrized by the ratio between these components of the field.

Sign in / Sign up

Export Citation Format

Share Document