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The Equation of State of Neutron Star Matter in Strong Magnetic Fields

Journal Article:

Abstract

We study the effects of very strong magnetic fields on the equation of state (EOS) in multicomponent, interacting matter by developing a covariant description for the inclusion of the anomalous magnetic moments of nucleons. For the description of neutron star matter, we employ a field-theoretical approach, which permits the study of several models that differ in their behavior at high density. Effects of Landau quantization in ultrastrong magnetic fields (B>10{sup 14} G) lead to a reduction in the electron chemical potential and a substantial increase in the proton fraction. We find the generic result for B>10{sup 18} G that the softening of the EOS caused by Landau quantization is overwhelmed by stiffening due to the incorporation of the anomalous magnetic moments of the nucleons. In addition, the neutrons become completely spin polarized. The inclusion of ultrastrong magnetic fields leads to a dramatic increase in the proton fraction, with consequences for the direct Urca process and neutron star cooling. The magnetization of the matter never appears to become very large, as the value of |H/B| never deviates from unity by more than a few percent. Our findings have implications for the structure of neutron stars in the presence of large frozen-in  More>>
Publication Date:
Jul 01, 2000
Product Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 537; Journal Issue: 1; Other Information: PBD: 1 Jul 2000
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; NEUTRON STARS; NUCLEAR MATTER; EQUATIONS OF STATE; MAGNETIC FIELDS; MAGNETIC MOMENTS; STAR MODELS; THEORETICAL DATA
OSTI ID:
20217424
Country of Origin:
United States
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0004-637X; ASJOAB; TRN: US00Z2475
Submitting Site:
AIP
Size:
page(s) 351-367
Announcement Date:

Journal Article:

Citation Formats

Broderick, A, Prakash, M, and Lattimer, J M. The Equation of State of Neutron Star Matter in Strong Magnetic Fields. United States: N. p., 2000. Web. doi:10.1086/309010.
Broderick, A, Prakash, M, & Lattimer, J M. The Equation of State of Neutron Star Matter in Strong Magnetic Fields. United States. doi:10.1086/309010.
Broderick, A, Prakash, M, and Lattimer, J M. 2000. "The Equation of State of Neutron Star Matter in Strong Magnetic Fields." United States. doi:10.1086/309010. https://www.osti.gov/servlets/purl/10.1086/309010.
@misc{etde_20217424,
title = {The Equation of State of Neutron Star Matter in Strong Magnetic Fields}
author = {Broderick, A, Prakash, M, and Lattimer, J M}
abstractNote = {We study the effects of very strong magnetic fields on the equation of state (EOS) in multicomponent, interacting matter by developing a covariant description for the inclusion of the anomalous magnetic moments of nucleons. For the description of neutron star matter, we employ a field-theoretical approach, which permits the study of several models that differ in their behavior at high density. Effects of Landau quantization in ultrastrong magnetic fields (B>10{sup 14} G) lead to a reduction in the electron chemical potential and a substantial increase in the proton fraction. We find the generic result for B>10{sup 18} G that the softening of the EOS caused by Landau quantization is overwhelmed by stiffening due to the incorporation of the anomalous magnetic moments of the nucleons. In addition, the neutrons become completely spin polarized. The inclusion of ultrastrong magnetic fields leads to a dramatic increase in the proton fraction, with consequences for the direct Urca process and neutron star cooling. The magnetization of the matter never appears to become very large, as the value of |H/B| never deviates from unity by more than a few percent. Our findings have implications for the structure of neutron stars in the presence of large frozen-in magnetic fields. (c) 2000 The American Astronomical Society.}
doi = {10.1086/309010}
journal = {Astrophysical Journal}
issue = {1}
volume = {537}
journal type = {AC}
place = {United States}
year = {2000}
month = {Jul}
}