Class Of Pulsars Research Articles

Astronomy: Neutron stars in Nanjing

Astronomy: Neutron stars in Nanjing

Upper Limit on the Frequency of Pulsars

Neutron stars for which the ratio $\frac{T}{|W|}$ of kinetic to gravitational potential energy exceeds \ensuremath{\sim} 0.08 are likely to be unstable and to spin down by gravitational-wave---driven oscillations. A class of pulsars with nearly identical frequencies may thus result from the collapse of accreting, rapidly rotating white dwarfs. It is likely that the fast pulsar, PSR 1937 + 214, rotates more slowly than this, but the question remains open partly because of uncertainty in the equation of state.

On the origin of pulsar ?nulling?

We show that depending on the type of pulsar evolutional model one adopts, the phenomenon of nulling is found to be either intrinsic to all pulsars, occurring during a particular stage of its life, or may be peculiar to only a class of pulsars.

Pulsar velocity observations - Correlations, interpretations, and discussion

view Abstract Citations (80) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Pulsar velocity observations: correlations, interpretations, and discussion. Helfand, D. J. ; Tademaru, E. Abstract A self-consistent picture of the dynamical evolution of pulsars is developed from an examination of the currently complete sample of pulsar proper motions. The apparent preference for pulsar velocities to be parallel to the galactic plane and the increase in observed transverse velocities with increasing galactic latitude are shown to result from various observational selection effects. The apparent motion of several pulsars toward the galactic plane is converted to an overall expansion of all pulsars from an origin in an extreme Population I distribution by simple vector addition of reasonable radial-velocity components. A strong correlation of velocity magnitude with the product of pulsar period and period derivative is noted, a dynamical value for pulsar magnetic-field decay time is derived, and it is concluded that there are two classes of pulsars distinguished by differences in mean velocity, scale height, and the value of the product of period and period derivative. A model is proposed to explain the origin of the two classes in terms of the presence or absence of a companion star to the supernova that created the neutron star. Publication: The Astrophysical Journal Pub Date: September 1977 DOI: 10.1086/155529 Bibcode: 1977ApJ...216..842H Keywords: Pulsars; Stellar Evolution; Stellar Motions; Astronomical Models; Companion Stars; Neutron Stars; Stellar Magnetic Fields; Astrophysics full text sources ADS | data products SIMBAD (13)

Tugboat model for OB binaries, X-ray stars and pulsars

An examination of the kinematical properties of binary OB stars, binary X-ray sources and pulsars suggests an evolutionary sequence linking an apparent low-velocity class of pulsars to the binary nature of their extreme Population I progenitors.

The secular variation of pulsar magnetic dipole moments

The time dependences of the inertia tensor and of a dissipative torque caused by the nonleptonic weak interaction have been investigated for a certain class of pulsars with no solid core. Early in the life of the pulsar, the angular velocity vector is predicted to move with respect to fixed body axes in such a way that it becomes perpendicular to the magnetic dipole moment. During this motion, the solid outer shell suffers plastic deformation so that the dipole moment becomes approximately collinear with a principal axis. After 104 or 105 yr, the dissipative torque is negligibly small compared with the electromagnetic torque, the Euler equations are those for a simple rigid body, and alignment of spin and dipole moment occurs. If the dipole moment discussed by Lyneet al. (1975) is interpreted as being equal to the component perpendicular to the spin, its secular decay is a natural property of this model and is not a consequence of field decay through electrical resistivity.