Relaxation by thermal conduction of a magnetically confined mountain on an accreting neutron star
arXiv:1812.10029 · doi:10.1093/mnras/sty3518
Abstract
A magnetically confined mountain on the surface of an accreting neutron star simultaneously reduces the global magnetic dipole moment through magnetic burial and generates a mass quadrupole moment, which emits gravitational radiation. Previous mountain models have been calculated for idealized isothermal and adiabatic equations of state. Here these models are generalised to include non-zero, finite thermal conduction. Grad-Shafranov equilibria for three representative, polytropic equations of state are evolved over many conduction time-scales with the magnetohydrodynamic solver PLUTO. It is shown that conduction facilitates the flow of matter towards the pole. Consequently the buried magnetic field is partially resurrected starting from an initially polytropic Grad-Shafranov equilibrium. The poleward mass current makes the star more prolate, marginally increasing its detectability as a gravitational wave source, though to an extent which is likely to be subordinate to other mountain physics. Thermal currents also generate filamentary hot spots in the mountain, especially near the pole where the heat flux is largest, with implications for type I X-ray bursts.
23 pages,17 figures, 3 tables. Accepted for publication in MNRAS
References in corpus (18)
- PLUTO: a Numerical Code for Computational Astrophysics
- Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
- The Magnetic Rayleigh-Taylor Instability in Three Dimensions
- Mountains on Neutron Stars: Accreted vs. Non-Accreted crusts
- Detecting gravitational waves from mountains on neutron stars in the Advanced Detector Era
- Thermoplastic waves in magnetars
- Burial of the polar magnetic field of an accreting neutron star. II. Hydromagnetic stability of axisymmetric equilibria
- Creation of magnetic spots at the neutron star surface
- Neutron star deformation due to poloidal-toroidal magnetic fields of arbitrary multipole order: a new analytic approach
- Resistive relaxation of a magnetically confined mountain on an accreting neutron star
- Improved estimate of the detectability of gravitational radiation from a magnetically confined mountain on an accreting neutron star
- Three-dimensional stability of magnetically confined mountains on accreting neutron stars
- MHD instabilities in accretion mounds - 1: 2D axisymmetric simulations
- Signature of Temporary Burning Front Stalling from a Non-Photospheric Radius Expansion Double-peaked Burst
- On the dependence of X-ray burst rate on accretion and spin rate
- Cyclotron line signatures of thermal and magnetic mountains from accreting neutron stars
- The Dynamics of Rayleigh-Taylor Stable and Unstable Contact Discontinuities with Anisotropic Thermal Conduction
- Continuous frequency spectrum of the global hydromagnetic oscillations of a magnetically confined mountain on an accreting neutron star
Cited by in corpus (8)
- Searches for Continuous-Wave Gravitational Radiation
- Ultra-compact X-ray binaries as dual-line gravitational-wave sources
- Magnetically confined mountains on accreting neutron stars with multipole magnetic fields
- Modelling spin-up episodes in accreting millisecond X-ray pulsars
- Premerger phenomena in neutron-star binary coalescences
- Magnetically Confined Mountains on Accreting Neutron Stars in General Relativity
- Universality of gravitational radiation from magnetar magnetospheres
- Dynamics of magnetoviscous warped discs around compact objects