Preprint calculates Magnus mountains on neutron stars yielding mass quadrupoles up to 10^{-5}
The preprint demonstrates that Magnus forces can sustain neutron-star deformations large enough for continuous gravitational-wave detection. The infinite-cylinder model yields quadrupoles limited by pinning and crustal strength. More realistic geometries and pinning microphysics are required before observational tests.
The study solves coupled fluid-elastic equations for a compressible two-component cylinder with a thin crust and ocean. Vortex pinning exerts a Magnus force that breaks axisymmetry, generating a mass quadrupole while the current quadrupole remains zero. The deformation saturates only at the limits of pinning strength and crustal breaking strain rather than equilibrium balance. This setup directly predicts continuous gravitational-wave emission at levels potentially reachable by advanced detectors.
Realistic spherical geometry, finite stellar radius, and magnetic-field evolution would alter both the force balance and the resulting quadrupole. Prior neutron-star mountain calculations focused on elastic or magnetic deformations; the Magnus mechanism introduces a rotation-dependent, vortex-mediated channel that scales with spin frequency and superfluid fraction. If pinning persists at the required levels, the effect could dominate over conventional mechanisms at high spin rates.
Next steps include three-dimensional simulations that incorporate realistic equations of state and vortex-creep dynamics, followed by targeted continuous-wave searches in LIGO-Virgo-KAGRA data for known pulsars. Confirmation would require both a detected signal amplitude matching the predicted quadrupole and independent constraints on crustal strain from glitch observations.
LIGO: No continuous-wave strain above 5e-27 from any known pulsar attributed to Magnus mountains by end of O5 run
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2608.12378)
- [2]Supporting Source(https://arxiv.org/abs/2007.03799)