Measuring neutron star mass and radius with three mass–radius relations

• Published in: Monthly notices of the Royal Astronomical Society Vol. 374; no. 1; pp. 232 - 236
• Main Authors: Zhang, C. M., Yin, H. X., Kojima, Y., Chang, H. K., Xu, R. X., Li, X. D., Zhang, B., Kiziltan, B.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-01-2007; Blackwell Science; Oxford University Press
• Subjects: Astronomy; Astrophysics; Earth, ocean, space; equation of state; Exact sciences and technology; Measurement techniques; pulsars: general; Stars & galaxies; stars: neutron; X-rays: stars; equation of state; X-rays: stars; pulsars: general; stars: neutron; Absorption line; Mass radius relation; Neutron stars; Equations of state; Stellar mass; Gravitational red shift; Pulsars; Quasi periodic variation
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2006.11133.x

We propose to determine the mass and radius of a neutron star (NS) using three measurable mass–radius relationships, namely the ‘apparent’ radius inferred from the NS thermal emission, the gravitational redshift inferred from the absorption lines, as well as the averaged stellar mass density inferred from the orbital Keplerian frequency derived from the kilohertz quasi-periodic oscillation data. We apply the method to constrain the NS mass and radius of the X-ray sources, 1E 1207.4−5209, Aql X-1 and EXO 0748−676.