ORIGINAL RESEARCH article
Front. Astron. Space Sci.
Sec. High-Energy and Astroparticle Physics
Volume 12 - 2025 | doi: 10.3389/fspas.2025.1625459
Braking Index of PSR J1846-0258: A Model of Magnetic Inclination Evolution and Its Gravitational-Wave Implication
Provisionally accepted
- 1Xinjiang Astronomical Observatory, National Astronomical Observatories, Chinese Academy of Sciences (CAS), Ürümqi, China
- 2School of Astronomy and Space Science, University of Chinese Academy of Sciences,, Beijing, China
- 3Xinjiang Key Laboratory of Radio Astrophysics,, Urumqi, China
- 4School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing, China
- 5Institute of Astrophysics, Central China Normal University, Wuhan, China
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We explain the braking index n = 2.19 ± 0.03 of PSR J1846-0258 by incorporating the time evolution of its magnetic inclination angle and dipolar magnetic field. Based on observational timing data and the age of the associated supernova remnant (t SNR ≈ 1.77kyr), we estimate a magnetic inclination change rate of χ ≈ 0.281 • /100yrs, comparable to that of the Crab pulsar.Applying the two-dipole model Hamil et al. (2016) to PSR J1846-0258, we find an internal dipole moment ratio η = M 2 /M 1 ∼ 10 26 -10 27 . For magnetic field decay timescales τ D < 3.6 × 10 5 yrs, the magnetic energy dissipation rate ( Ėmag ∼ (10 33 -10 34 ) erg/s) partially explains the observed X-ray luminosity L X ∼ 1.9 × 10 34 erg/s, while longer τ D requires additional energy sources. The derived gravitational wave strain (h 0 ∼ 10 -29 ) remains undetectable with current instruments but constrains internal magnetic field geometries. This work highlights the critical role of magnetic inclination dynamics in pulsar spin-down behavior and offers a physically motivated framework that can be extended to other young neutron stars with measured magnetic inclination and braking indices.
Keywords: neutron stars, PSR J1846-0258, magnetic inclination angle, magnetic field, magnetars, braking index
Received: 09 May 2025; Accepted: 23 Jun 2025.
Copyright: © 2025 Li, Gao, Ma and Cheng. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Zhi Fu Gao, Xinjiang Astronomical Observatory, National Astronomical Observatories, Chinese Academy of Sciences (CAS), Ürümqi, China
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