RELATIONS BETWEEN NEUTRON-STAR PARAMETERS IN THE HARTLE-THORNE APPROXIMATION

Journal Article · Fri Nov 01 00:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/777/1/68· OSTI ID:22270637

Bauböck, Michi; Psaltis, Dimitrios; Özel, Feryal ^[1]; Berti, Emanuele ^[2]

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1. Astronomy Department, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
2. Department of Physics and Astronomy, The University of Mississippi, University, MS 38677 (United States)

Using stellar structure calculations in the Hartle-Thorne approximation, we derive analytic expressions connecting the ellipticity of the stellar surface to the compactness, the spin angular momentum, and the quadrupole moment of the spacetime. We also obtain empirical relations between the compactness, the spin angular momentum, and the spacetime quadrupole. Our formulae reproduce the results of numerical calculations to within a few percent and help reduce the number of parameters necessary to model the observational appearance of moderately spinning neutron stars. This is sufficient for comparing theoretical spectroscopic and timing models to observations that aim to measure the masses and radii of neutron stars and to determine the equation of state prevailing in their interiors.

• OSTI ID: 22270637
• Journal Information: Astrophysical Journal, Vol. 777, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
APPROXIMATIONS
ASTRONOMY
ASTROPHYSICS
COMPARATIVE EVALUATIONS
EQUATIONS OF STATE
GRAVITATION
MASS
NEUTRON STARS
QUADRUPOLE MOMENTS
RELATIVISTIC RANGE
SPACE-TIME
SURFACES