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X-ray pulsars: their masses, radii and equations of state

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Abstract

The semi-empirical mass — radius relations of X-ray pulsars, which depend on the ‘exterior’ behavior of X-ray pulsars, are calculated for four X-ray pulsars, Cen X-3, 4U 1626–67, Her X-1 and EXO 2030+375, based on the observed data and our modified accretion torque model. Comparison between the calculated and the theoretical mass — radius relations shows that three of them, Cen X-3, 4U 1626–67 and EXO 2030+375, are consistent with the stiff or intermediate stiff equations of state, yielding the masses and radii around the typical values of neutron stars. Her X-1 seems not to be well described by the standard equations of state, though it may be reconciled with the soft equation of state.

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Authors and Affiliations

  1. Department of Astronomy, Nanjing University, 210093, Nanjing, P.R. China

    Xiangdong Li & Zhenru Wang

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  1. Xiangdong Li
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  2. Zhenru Wang
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Li, X., Wang, Z. X-ray pulsars: their masses, radii and equations of state. Astrophys Space Sci 234, 39–48 (1995). https://doi.org/10.1007/BF00627280

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  • DOI: https://doi.org/10.1007/BF00627280

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