Neutron Star Atmosphere–Ocean Dynamics

Joonas Nättilä; James Y-K. Cho; Jack W. Skinner; Elias R. Most; Bart Ripperda

doi:10.3847/1538-4357/ad54c2

The Astrophysical Journal (Jan 2024)

Neutron Star Atmosphere–Ocean Dynamics

Joonas Nättilä,
James Y-K. Cho,
Jack W. Skinner,
Elias R. Most,
Bart Ripperda

Affiliations

Joonas Nättilä: ORCiD; Department of Physics, University of Helsinki , Gustaf Hällströmin katu 2, Helsinki, FI 00014, Finland ; [email protected]; Physics Department and Columbia Astrophysics Laboratory, Columbia University , 538 West 120th Street, New York, NY 10027, USA; Center for Computational Astrophysics, Flatiron Institute , 162 Fifth Avenue, New York, NY 10010, USA
James Y-K. Cho: ORCiD; Center for Computational Astrophysics, Flatiron Institute , 162 Fifth Avenue, New York, NY 10010, USA; Martin A. Fisher School of Physics, Brandeis University , 415 South Street, Waltham, MA 02453, USA
Jack W. Skinner: ORCiD; Martin A. Fisher School of Physics, Brandeis University , 415 South Street, Waltham, MA 02453, USA; Division of Geological and Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USA
Elias R. Most: ORCiD; TAPIR, MC 350-17, California Institute of Technology , Pasadena, CA 91125, USA; Walter Burke Institute for Theoretical Physics, California Institute of Technology , Pasadena, CA 91125, USA
Bart Ripperda: ORCiD; Center for Computational Astrophysics, Flatiron Institute , 162 Fifth Avenue, New York, NY 10010, USA; Canadian Institute for Theoretical Astrophysics , 60 St. George Street, Toronto, Ontario M5S 3H8, Canada; Department of Physics, University of Toronto , 60 St. George Street, Toronto, ON M5S 1A7, Canada; David A. Dunlap Department of Astronomy, University of Toronto , 50 St. George Street, Toronto, ON M5S 3H4, Canada; Perimeter Institute for Theoretical Physics , 31 Caroline Street North, Waterloo, ON N2L 2Y5, Canada

DOI: https://doi.org/10.3847/1538-4357/ad54c2
Journal volume & issue: Vol. 971, no. 1
p. 37

Abstract

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We analyze the structure and dynamics of the plasma atmospheres and Coulomb-liquid oceans on neutron stars. Salient dynamical parameters are identified and their values estimated for the governing set of magnetohydrodynamics equations. Neutron star atmospheres and oceans are strongly stratified and, depending on the rotation period, contain a multitude of long-lived vortices (spots) and/or narrow zonal jets (free-shear zones) in the large plasma-beta regime—i.e., β _p ≫ 1 (hydrodynamic regime). In contrast, when β _p ≲ 1 (magnetohydrodynamic regime), the flow is dominated by a global lattice of effectively fixed magnetic islands (plasmoids) without any jets. Understanding the spatiotemporal variability of dynamic atmospheres and oceans on neutron stars is crucial for interpreting observations of their X-ray emissions.

Published in The Astrophysical Journal

ISSN: 1538-4357 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy: Astrophysics
Website: https://iopscience.iop.org/journal/0004-637X

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