Magnetic Inclination Evolution of Accreting Neutron Stars in Intermediate/Low-Mass X-ray Binaries

Abstract

The magnetic inclination angle $\chi$, namely the angle between the spin and magnetic axes of a neutron star (NS), plays a vital role in its observational characteristics. However, there are few systematic investigations on its long-term evolution, especially for accreting NSs in binary systems. Applying the model of \citet{2021MNRAS.505.1775B} and the binary evolution code \mesa{}, we simultaneously simulate the evolution of the accretion rate, spin period, magnetic field, and magnetic inclination angle of accreting NSs in intermediate/low X-ray binaries (I/LMXBs). We show that the evolution of $\chi$ depends not only on the initial parameters of the binary systems, but also on the mass transfer history and the efficiency of pulsar loss. Based on the calculated results we present the characteristic distribution of $\chi$ for various types of systems including ultracompact X-ray binaries, binary millisecond pulsars, and ultraluminous X-ray sources, and discuss their possible observational implications.

12 pages, 7 figures, accepted for publication in ApJ

References in corpus (6)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Accretion funnels onto weakly magnetized young stars
• Constraints on the Emission Geometries and Spin Evolution of Gamma-ray Millisecond Pulsars
• The Effect of Transient Accretion on the Spin-Up of Millisecond Pulsars
• Constraining compactness and magnetic field geometry of X-ray pulsars from the statistics of their pulse profiles

Cited by in corpus (3)

• Two-temperature accretion flows around strongly magnetized stars and their spectral analysis
• A short review of the pulsar magnetic inclination angles (II)
• Effect of irradiation on the spin of millisecond pulsars