Anisotropic neutron star crust, solar system mountains, and gravitational waves

Abstract

"Mountains" or non-axisymmetric deformations of rotating neutron stars (NS) efficiently radiate gravitational waves (GW). We consider analogies between NS mountains and surface features of solar system bodies. Both NS and moons such as Europa or Enceladus have thin crusts over deep oceans while Mercury has a thin crust over a large metallic core. Thin sheets may wrinkle in universal ways. Europa has linear features, Enceladus has "Tiger" stripes, and Mercury has lobate scarps. NS may have analogous features. The innermost inner core of the Earth is anisotropic with a shear modulus that depends on direction. If NS crust material is also anisotropic this will produce an ellipticity, when the crust is stressed, that grows with spin frequency. This yields a braking index (log derivative of spin down rate assuming only GW spin down) very different from $n=5$ and could explain the maximum spin observed for neutron stars and a possible minimum ellipticity of millisecond pulsars.

arXiv comment8 pages, 2 figures, Added finite element simulations that confirm results, PRD in press

References in corpus (59)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
• Deformations of Accreting Neutron Star Crusts and Gravitational Wave Emission
• The Breaking Strain of Neutron Star Crust and Gravitational Waves
• Construction of arbitrary order finite element degree-of-freedom maps on polygonal and polyhedral cell meshes
• Beating the spin-down limit on gravitational wave emission from the Crab pulsar
• Setting upper limits on the strength of periodic gravitational waves using the first science data from the GEO600 and LIGO detectors
• Wrinkling hierarchy in constrained thin sheets from suspended graphene to curtains
• Upper limits on gravitational wave emission from 78 radio pulsars
• First search for gravitational waves from known pulsars with Advanced LIGO
• Gravitational waves from known pulsars: results from the initial detector era
• Limits on gravitational wave emission from selected pulsars using LIGO data
• Coherent searches for periodic gravitational waves from unknown isolated sources and Scorpius X-1: results from the second LIGO science run
• Beating the spin-down limit on gravitational wave emission from the Vela pulsar
• Searches for gravitational waves from known pulsars with S5 LIGO data
• Liquid crystals in the mantles of neutron stars
• Breaking stress of neutron star crust
• All-sky search for periodic gravitational waves in LIGO S4 data
• The Einstein@Home search for periodic gravitational waves in LIGO S4 data
• Searches for Continuous-Wave Gravitational Radiation
• Searches for Gravitational Waves from Known Pulsars at Two Harmonics in 2015-2017 LIGO Data
• First search for nontensorial gravitational waves from known pulsars
• Astromaterial Science and Nuclear Pasta
• Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data
• All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data
• Search for gravitational waves from Scorpius X-1 in the first Advanced LIGO observing run with a hidden Markov model
• First all-sky upper limits from LIGO on the strength of periodic gravitational waves using the Hough transform
• Evidence for a minimum ellipticity in millisecond pulsars
• Narrow-band search for gravitational waves from known pulsars using the second LIGO observing run
• Upper Limits on Gravitational Waves from Scorpius X-1 from a Model-Based Cross-Correlation Search in Advanced LIGO Data
• The Elasticity of Nuclear Pasta
• All-sky Search for Periodic Gravitational Waves in the Full S5 LIGO Data
• Full Band All-sky Search for Periodic Gravitational Waves in the O1 LIGO Data
• Narrowband searches for continuous and long-duration transient gravitational waves from known pulsars in the LIGO-Virgo third observing run
• Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs
• Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
• First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data
• Modelling neutron star mountains
• Search for continuous gravitational waves from 20 accreting millisecond X-ray pulsars in O3 LIGO data
• A directed search for gravitational waves from Scorpius X-1 with initial LIGO
• Results from the first all-sky search for continuous gravitational waves from small-ellipticity sources
• Narrow-band search of continuous gravitational-wave signals from Crab and Vela pulsars in Virgo VSR4 data
• Search for Continuous Gravitational Waves from Scorpius X-1 in LIGO O2 Data
• Deep Einstein@Home all-sky search for continuous gravitational waves in LIGO O3 public data
• Directed search for continuous gravitational-wave signals from the Galactic Center in the Advanced LIGO second observing run
• Comprehensive All-sky Search for Periodic Gravitational Waves in the Sixth Science Run LIGO Data
• Neutron Star Crust Can Support A Large Ellipticity
• Results from an Einstein@Home search for continuous gravitational waves from Cassiopeia A, Vela Jr. and G347.3
• Elastic properties of phases with nonspherical nuclei in dense matter
• Continuous gravitational waves from Galactic neutron stars: demography, detectability and prospects
• Directed searches for continuous gravitational waves from twelve supernova remnants in data from Advanced LIGO's second observing run
• Search for gravitational waves from twelve young supernova remnants with a hidden Markov model in Advanced LIGO's second observing run
• New searches for continuous gravitational waves from seven fast pulsars
• Loosely coherent search in LIGO O1 data for continuous gravitational waves from Terzan 5 and the galactic center
• The search for continuous gravitational waves from small-ellipticity sources at low frequencies
• First searches for gravitational waves from r-modes of the Crab pulsar
• A frequency resolved atlas of the sky in continuous gravitational waves
• Results from an Einstein@Home search for continuous gravitational waves from G347.3 at low frequencies in LIGO O2 data

Cited by in corpus (6)

• Properties of the Object HESS J1731-347 as a Twin Compact Star
• Results from an Einstein@Home search for continuous gravitational waves from Cassiopeia A and Vela Jr. using LIGO O2 data
• Continuous gravitational waves from thermal mountains on accreting neutron stars: effect of the nuclear pasta phase
• Constraining shear modulus of polycrystalline neutron star crust: Hashin-Shtrikman variational approach
• Sco X-1 as a continuous gravitational waves source: modelling the secular evolution using MESA
• High-frequency continuous gravitational waves searched in LIGO O3 public data with Einstein@Home