scholarly journals Seven pulsars in binary systems above the spin-up line

2012 ◽  
Vol 8 (S291) ◽  
pp. 462-464
Author(s):  
Y. Y. Pan ◽  
N. Wang
Keyword(s):  
Magnetic Field ◽  
Binary Systems ◽  
Spin Period ◽  
Binary Pulsars ◽  
Field Versus ◽  
Using Data ◽  
The Magnetic Field

AbstractUsing data from the ATNF pulsar catalogue, 186 binary pulsars are shown in the magnetic field versus spin period (B-P) diagram, and their relationship to the spin-up line is investigated. Generally speaking, pulsars in binary systems should be below the spin-up line when they get enough accretion mass from their companions. It is found that there are seven binary pulsars above the spin-up line. Based on the parameters of these seven binary systems, we describe possible reasons why they are above the spin-up line.

scholarly journals Minimum accretion rate for millisecond pulsar formation in binary system

2012 ◽  
Vol 8 (S290) ◽  
pp. 291-292
Author(s):  
Yuanyue Pan ◽  
Chengmin Zhang ◽  
Na Wang
Keyword(s):  
Magnetic Field ◽  
Binary System ◽  
Accretion Rate ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Spin Period ◽  
Binary Pulsars ◽  
Field Versus ◽  
The Magnetic Field

Abstract186 binary pulsars are shown in the magnetic field versus spin period (B-P) diagram, and their relations to the millisecond pulsars can be clearly seen. We declaim a minimum accretion rate for the millisecond pulsar formation both from the observation and theory. If the accretion rate is lower than the minimum accretion rate, the pulsar in binary system will not become a millisecond pulsar after the evolution.

scholarly journals Binary pulsars in magnetic field versus spin period diagram

2013 ◽  
Vol 346 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Y. Y. Pan ◽  
N. Wang ◽  
C. M. Zhang
Keyword(s):  
Magnetic Field ◽  
Spin Period ◽  
Binary Pulsars ◽  
Field Versus

THE SPIN-UP OF ACCRETING NEUTRON STARS IN BINARY SYSTEMS

2011 ◽  
Vol 20 (10) ◽  
pp. 2019-2022
Author(s):  
J. WANG ◽  
C. M. ZHANG ◽  
Y. H. ZHAO
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Binary Systems ◽  
Initial Conditions ◽  
Initial Period ◽  
Spin Period ◽  
The Magnetic Field ◽  
Initial Magnetic Field

In binary systems, the rotation of neutron stars can be spun up by the accreted material, and at the same time the decay of their magnetic fields occur in the accretion phase. As a result, the spin period may arrive at a minimum of about 1.5 ms, corresponding to a bottom value of the magnetic field ~ 108 G. Taking the conditions: (i) initial magnetic field varying from 1011 G to 1013 G while setting period as 100 s, (ii) initial period as 1–100 s at B = 5 × 1012 G , we find that this minimum of spin period seems independent of these initial conditions.

THE SATURATED MAGNETIC FIELD OF THE NEUTRON STARS

2000 ◽  
Vol 09 (01) ◽  
pp. 1-12 ◽  
Author(s):  
C. M. ZHANG
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Neutron Star ◽  
Neutron Stars ◽  
Thermal Effect ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Spin Period ◽  
Field Versus ◽  
The Magnetic Field

Considering the ferromagnetic screening for the decay of the X-ray neutron star magnetic field in the binary accretion phase, the phase transition of ferromagnetic materials in the crust of neutron star induces the ferromagnetic screening saturation of the accreted crust, which results in the minimum surface magnetic field of the accreting neutron star, about 108 G, if the accreted matter has completely replaced the crust mass of the neutron star. The magnetic field evolution versus accreted mass is given as [Formula: see text], and the obtained magnetic field versus spin period relation is consistent with the distribution of the binary X-ray sources and recycled pulsars. The further thermal effect on the magnetic evolution is also studied.

scholarly journals Early neutron star evolution in high-mass X-ray binaries

2020 ◽  
Vol 494 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Wynn C G Ho ◽  
M J P Wijngaarden ◽  
Nils Andersson ◽  
Thomas M Tauris ◽  
F Haberl
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Thermal Emission ◽  
Equilibrium Phase ◽  
High Mass ◽  
X Ray ◽  
Spin Period ◽  
Long Duration ◽  
X Ray Binaries ◽  
The Magnetic Field

ABSTRACT The application of standard accretion theory to observations of X-ray binaries provides valuable insights into neutron star (NS) properties, such as their spin period and magnetic field. However, most studies concentrate on relatively old systems, where the NS is in its late propeller, accretor, or nearly spin equilibrium phase. Here, we use an analytic model from standard accretion theory to illustrate the evolution of high-mass X-ray binaries (HMXBs) early in their life. We show that a young NS is unlikely to be an accretor because of the long duration of ejector and propeller phases. We apply the model to the recently discovered ∼4000 yr old HMXB XMMU J051342.6−672412 and find that the system’s NS, with a tentative spin period of 4.4 s, cannot be in the accretor phase and has a magnetic field B > a few × 1013 G, which is comparable to the magnetic field of many older HMXBs and is much higher than the spin equilibrium inferred value of a few × 1011 G. The observed X-ray luminosity could be the result of thermal emission from a young cooling magnetic NS or a small amount of accretion that can occur in the propeller phase.

RADIO-FREQUENCY EREAKDOWN CONTROLLED BY DRIFT OF ELECTRONS IN AN INHOMOGENEOUS MAGNETIC FIELD

1961 ◽  
Vol 39 (7) ◽  
pp. 983-992
Author(s):  
L. T. Shepherd ◽  
H. M. Skarsgard
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Radio Frequency ◽  
Inhomogeneous Magnetic Field ◽  
Breakdown Field ◽  
Electron Theory ◽  
Loss Mechanism ◽  
Field Versus ◽  
Average Electron ◽  
The Magnetic Field

A study has been made of r-f. breakdown in which the controlling loss mechanism arises from the drift of electrons in an inhomogeneous magnetic field. The study was carried out using a toroidal system with parallel r-f. electric and steady magnetic fields. An approximate average-electron theory of drift-controlled breakdown is presented. Experimental measurements of breakdown r-f. electric field versus magnetic field were made at various pressures from 1.25 to 6.0 × 10−3 mm of Hg, using hydrogen and helium gases. A radio frequency of 8 Mc/sec was used. Magnetic fields up to 2000 gauss were employed. The r-f. breakdown field was found to vary as the inverse square root of the magnetic field as predicted by the theory.

scholarly journals Starspots Magnetic field by transit mapping

2013 ◽  
Vol 9 (S302) ◽  
pp. 220-221
Author(s):  
Adriana Válio ◽  
Eduardo Spagiari
Keyword(s):  
Magnetic Field ◽  
Light Curve ◽  
Field Component ◽  
Solar Magnetic Field ◽  
Line Of Sight ◽  
The Sun ◽  
Using Data ◽  
The Magnetic Field ◽  
Spot Temperature

AbstractSunspots are important signatures of the global solar magnetic field cycle. It is believed that other stars also present these same phenomena. However, today it is not possible to observe directly star spots due to their very small sizes. The method applied here studies star spots by detecting small variations in the stellar light curve during a planetary transit. When the planet passes in front of its host star, there is a chance of it occulting, at least partially, a spot. This allows the determination of the spots physical characteristics, such as size, temperature, and location on the stellar surface. In the case of the Sun, there exists a relation between the magnetic field and the spot temperature. We estimate the magnetic field component along the line-of-sight and the intensity of sunspots using data from the MDI instrument on board of the SOHO satellite. Assuming that the same relation applies to other stars, we estimate spots magnetic fields of CoRoT-2 and Kepler-17 stars.

scholarly journals Periodically repeating fast radio bursts: Lense–Thirring precession of a debris disk?

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
Wen-Cong Chen
Keyword(s):  
Magnetic Field ◽  
Rotational Energy ◽  
Radio Bursts ◽  
Spin Period ◽  
Disk Mass ◽  
Debris Disk ◽  
The Magnetic Field ◽  
Normal Magnetic Field ◽  
Current Stage ◽  
Tilted Disk

Abstract Recently, repeating fast radio bursts (FRBs) with a period of PFRB = 16.35 ± 0.18 d from FRB 180916.J0158+65 were reported. It still remains controversial how such a periodicity might arise for this FRB. In this Letter, based on an assumption of a young pulsar surrounding by a debris disk, we attempt to diagnose whether Lense–Thirring precession of the disk on the emitter can produce the observed periodicity. Our calculations indicate that the Lense–Thirring effect of a tilted disk can result in a precession period of 16 d for a mass inflow rate of 0.5–1.5 × 1018 g s−1, a pulsar spin period of 1–20 ms, and an extremely low viscous parameter α = 10−8 in the disk. The disk mass and the magnetic field of the pulsar are also constrained to be ∼10−3 M⊙ and <2.5 × 1013 G. In our model, a new-born pulsar with normal magnetic field and millisecond period would successively experience the accretion and propeller phases, and is visible as a strong radio source in the current stage. The rotational energy of such a young neutron star can provide the observed radio bursting luminosity for 400 yr.

scholarly journals Understanding the coexistence of spin-up and spin-down behaviours in long-period X-ray pulsars

2020 ◽  
Vol 492 (1) ◽  
pp. 762-769
Author(s):  
W Wang ◽  
H Tong
Keyword(s):  
Magnetic Field ◽  
Binary Systems ◽  
Accretion Rate ◽  
Constant Mass ◽  
X Ray ◽  
Spin Period ◽  
Long Period ◽  
Rotational Evolution ◽  
Order Of Magnitude ◽  
Field Decay

ABSTRACT Assuming wind-fed accretion magnetars in long-period X-ray pulsars, we calculated the rotational evolution of neutron stars. Our calculations considered the effects of magnetic field decay in magnetars. The results show that wind-fed accretion magnetars can evolve to long-period X-ray pulsars with a spin period much longer than 1000 s. The spin-down trend observed in 4U 2206+54-like sources is expected when young X-ray binary systems are on the way to their equilibrium period. Detailed calculations showed that the spin-down may be affected by accretion with outflows or accretion while spinning down. Due to magnetic field decay in magnetars, wind-fed accretion magnetars will have a decreasing equilibrium period for a constant mass accretion rate. For 2S 0114+65, the spin-up rate due to magnetic field decay is one order of magnitude smaller than observations. The spin-up rate of 2S 0114+65 may be attributed to the formation of a transient disc during wind accretion. The slowest X-ray pulsar AX J1910.7+0917 would be a link source between 4U 2206+54 and 2S 0114+65.

scholarly journals Magneto-hydrodynamical origin of eclipsing time variations in post-common-envelope binaries for solar mass secondaries

2019 ◽  
Author(s):  
Felipe H Navarrete ◽  
Dominik R G Schleicher ◽  
Petri J Käpylä ◽  
Jennifer Schober ◽  
Marcel Völschow ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quadrupole Moment ◽  
Binary Systems ◽  
Solar Rotation ◽  
Solar Mass ◽  
Common Envelope ◽  
Time Variations ◽  
Rapid Rotator ◽  
The Magnetic Field ◽  
Solar Rotation Rate

Abstract Eclipsing time variations have been observed for a wide range of binary systems, including post-common-envelope binaries. A frequently proposed explanation, apart from the possibility of having a third body, is the effect of magnetic activity, which may alter the internal structure of the secondary star, particularly its quadrupole moment, and thereby cause quasi-periodic oscillations. Here we present two compressible non-ideal magneto-hydrodynamical (MHD) simulations of the magnetic dynamo in a solar mass star, one of them with three times the solar rotation rate (“slow rotator”), the other one with twenty times the solar rotation rate (“rapid rotator”), to account for the high rotational velocities in close binary systems. For the slow rotator, we find that both the magnetic field and the stellar quadrupole moment change in a quasi-periodic manner, leading to O-C (observed - corrected times of the eclipse) variations of ∼0.025 s. For the rapid rotator, the behavior of the magnetic field as well as the quadrupole moment changes become considerably more complex, due to the less coherent dynamo solution. The resulting O-C variations are of the order 0.13 s. The observed system V471 Tau shows two modes of eclipsing time variations, with amplitudes of 151 s and 20 s, respectively. However, the current simulations may not capture all relevant effects due to the neglect of the centrifugal force and self-gravity. Considering the model limitations and that the rotation of V471 Tau is still a factor of 2.5 faster than our rapid rotator, it may be conceivable to reach the observed magnitudes.

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