Magnetic quadri-dipolar stars rotating in vacuum

Abstract

Main sequence stars and compact objects like white dwarfs and neutron stars are usually embedded in magnetic fields that strongly deviate from a pure dipole located right at the stellar centre. An off-centred dipole can sometimes better adjust existing data and offer a simple geometric picture to include multipolar fields. However, such configurations are usually to restrictive, limiting multipolar components to strength less than the underlying dipole. In this paper, we consider the most general lowest order multipolar combination given by a dipole and a quadrupole magnetic field association in vacuum. Following the general formalism for multipolar field computations, we derive the full electromagnetic field outside a rotating quadridipole. Exact analytical expressions for the Poynting flux and the electromagnetic kick are given. Such geometry is useful to study the magnetosphere of neutron stars for which more and more compelling observations reveals hints for at least quadridipolar fields. We also show that for sufficiently high quadrupole components at the stellar surface, the electromagnetic kick imprinted to a neutron star can reach thousands of km/s for a millisecond period at birth.

11 pages, 15 figures, accepted for publication in MNRAS

References in corpus (13)

• PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
• A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation
• The ATNF Pulsar Catalogue
• The Oblate Schwarzschild Approximation for Light Curves of Rapidly Rotating Neutron Stars
• A NICER view of PSR J0030+0451: evidence for a global-scale multipolar magnetic field
• Universality of the Acceleration Due to Gravity on the Surface of a Rapidly Rotating Neutron Star
• Evidence for alignment of the rotation and velocity vectors in pulsars. II. Further data and emission heights
• Multipolar electromagnetic fields around neutron stars: exact vacuum solutions and related properties
• The birth properties of Galactic millisecond radio pulsars
• The illusion of neutron star magnetic field estimates
• Joint radio and X-ray modelling of PSR~J1136+1551
• Radiation from an off-centred rotating dipole in vacuum
• Kick velocity induced by magnetic dipole and quadrupole radiation

Cited by in corpus (5)

• The Multipolar Magnetic Field of Millisecond Pulsar PSR J0030+0451
• The Thousand-Pulsar-Array programme on MeerKAT XI: Application of the rotating vector model
• Evolution of Spin Period and Magnetic Field of the Crab Pulsar: Decay of the Braking Index by the Particle Wind Flow Torque
• Migrating Dynamo Waves and Consequences for Stellar Current Sheets
• Off-centred force-free neutron star magnetospheres