The Radius Estimation of Double Pulsar PSR J0737-3039A

AbstractWe investigate the radius of the recycled pulsar in double pulsar PSR J0737-3039. In the standard accretion spin-up model, the recycled pulsar spin up continues until arriving at a minimum spin period, or so-called “equilibrium period”, which is related to stellar magnetic field, accretion rate, mass and radius. If present spin period is much longer than that at birth, the spin-down age can give the realistic true age estimation for normal pulsar J0737-3039B. Base on the above conditions, we estimate the radius of millisecond pulsar (MSP) J0737-3039A by assuming its true age is same as the spin-down age of its companion J0737-3039B. We obtained that the radius of J0737-3039A ranges approximately from 5 to 27 km.

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Minimum accretion rate for millisecond pulsar formation in binary system

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312020066 ◽

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.

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RADIUS CONSTRAINT OF THE RECYCLED DOUBLE PULSAR PSR J0737-3039

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194513011252 ◽

2013 ◽

Vol 23 ◽

pp. 170-173

Author(s):

HAIHUI ZHAO ◽

LIMING SONG ◽

CHENGMIN ZHANG

Keyword(s):

Magnetic Field ◽

Strange Quark ◽

Accretion Rate ◽

Millisecond Pulsar ◽

Spin Period ◽

The One ◽

Radius Constraint

We investigate the radius of the recycled pulsar in double pulsar system PSR J0737-3039. In the standard accretion spin-up model, the recycled pulsar spin up continues until arriving at a minimum spin period, or so-called "equilibrium period", which is related to the stellar magnetic field, the accretion rate and radius. The generic spin-down age may give realistic estimates for normal pulsar PSR J0737-3039B, since its present spin period is much longer than the one at birth. In this paper, we estimate the radius of millisecond pulsar (MSP) PSR J0737-3039A by assuming its true age is same as the spin-down age of its companion PSR J0737-3039B. We find that the radius of recycled pulsar PSR J0737-3039A ranges approximately from 12 to 38 km, and it should be far from the composition of strange quark matters, as shown in the mass-radius diagram.

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3459 ◽

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.

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CHARACTERISTIC AGE AND TRUE AGE OF PULSARS

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194513011124 ◽

2013 ◽

Vol 23 ◽

pp. 95-98

Author(s):

LONG JIANG ◽

CHENG-MIN ZHANG ◽

ALI TANNI ◽

HAI-HUI ZHAO

Keyword(s):

Magnetic Field ◽

Monte Carlo Simulation ◽

Monte Carlo ◽

Millisecond Pulsar ◽

Spin Period ◽

Field Evolution ◽

Period Derivative ◽

The Difference ◽

The Relationship ◽

The Magnetic Field

Age of a pulsar is a useful parameter, but it is difficult to get the age from observation. We can only derive the characteristic age from the observed parameters: spin period (P) and period derivative (Ṗ). In this paper, we discussed the relationship between characteristic age and magnetic field of a pulsar. Monte Carlo simulation is also used to support the idea: it is useless to study the magnetic field evolution using characteristic age. From some observation evidences we get that: the characteristic age cannot be used as true age, especially for millisecond pulsar (MSP). The difference between them is also discussed. From the studying of breaking index and MSP's initial spin period (P0), we get the conclusion that: the problem cannot be resolved using different radiation models.

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The Magnetic Field of the Intermediate Polar RE 0751+14

International Astronomical Union Colloquium ◽

10.1017/s0252921100038586 ◽

1996 ◽

Vol 158 ◽

pp. 183-183

Author(s):

H. Väth

Keyword(s):

Magnetic Field ◽

White Dwarf ◽

Accretion Rate ◽

Shock Structure ◽

Light Curves ◽

X Rays ◽

Strong Magnetic Fields ◽

X Ray ◽

Spin Period ◽

The Magnetic Field

Piirola, Hakala & Coyne (1993) modeled the optical/IR light curve of RE 0751+14 assuming a uniform shock structure and neglecting the hard X-ray emission. In this paper, we model the light curves at optical/IR and hard X-ray wavelengths and include the effects of the shock structure.We base our model on accretion onto a white dwarf with a displaced magnetic dipole for a range of likely white dwarf masses. We find that the observed intensity variations of X-rays and in the I band over one spin period largely determine the position of the emission regions. Furthermore, the observed maximum X-ray flux constrains the specific accretion rate. We deduce that the magnetic field at the pole is likely to be in the range 9 .. .21 MG, which is consistent with the estimates of Piirola et al. (1993). It had been proposed previously that there must exist asynchronous rotators with sufficiently strong magnetic fields such that the binaries will evolve into AM Her binaries (Chanmugam & Ray 1984; King, Frank & Ritter 1985). With this deduced high magnetic field RE 0751+14 is the most likely example of such a system known to date.

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Questions on accreting mass and minimum magnetic field of millisecond pulsars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313000033 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 583-585

Author(s):

C. M. Zhang

Keyword(s):

Magnetic Field ◽

Binary System ◽

Accretion Rate ◽

Millisecond Pulsar ◽

Solar Mass ◽

Initial Field ◽

Millisecond Pulsars ◽

Mass Accretion Rate ◽

Polar Magnetic Field ◽

Minimum Value

AbstractAbout 0.2 solar mass is absorbed by the millisecond pulsar (MSP) at the binary accretion phase, while the polar magnetic field of MSP is diluted to a magnitude of order 108.5 Gauss, which is proportionally related to the mass accretion rate. It is found that the minimum magnetic field of MSP can be as low as 107 Gauss if the accretion rate of the binary system reaches its the minimum value of 1015 g/s. This bottom field has nothing to do with the MSP initial field. Some questions on MPSs are proposed and answered.

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On the bottom spin period and magnetic field of millisecond pulsar

10.1063/1.2900297 ◽

2008 ◽

Author(s):

C. M. Zhang ◽

C. Bassa ◽

Z. Wang ◽

A. Cumming ◽

V. M. Kaspi

Keyword(s):

Magnetic Field ◽

Millisecond Pulsar ◽

Spin Period

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Jet and kHz QPO-Accreting Pulsar and Bottom Magnetic Field

Proceedings of the International Astronomical Union ◽

10.1017/s174392131202039x ◽

2012 ◽

Vol 8 (S290) ◽

pp. 357-358

Author(s):

Yuanyue Pan ◽

Chengmin Zhang

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Field Strength ◽

Neutron Stars ◽

Magnetic Field Strength ◽

Accretion Rate ◽

Viewing Angle ◽

Millisecond Pulsar ◽

Jet Formation ◽

Jet Production

AbstractThe bottom magnetic fields of neutron stars (NSs) in LMXBs are found to be proportionally related to their accretion rate, i.e. Z (Atoll) source with Eddington (less Eddington) rate is associated with a stronger value of about B ~109 G (B ~108 G). We discuss the relation between the jet formation of NS and its bottom magnetic field strength, and pointed out that the accretion powered millisecond pulsar will not exclude the jet production, furthermore the appearance of kHz QPOs may be also coexistence with the jets. The observer's viewing angle to the NS rotating axis may be a significant factor for observing the jet, pulsar or kHz QPO.

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