标题： SAX J1808.4-3658中子星半径的严格上限 显示英文标题

标题： A Firm Upper Limit to the Radius of the Neutron Star in SAX J1808.4-3658

摘要： 我们表明，来自SAX J1808.4-3658的X射线脉冲观测对中子星半径给出了一个严格的上限，即13.8 m^{1/3}km，其中m为其质量（以太阳质量为单位）。 这一限制与距离或磁层几何结构的假设无关，并且未来对脉冲的观测可能会显著收紧这一限制。 我们讨论了这一结果对状态方程以及可能的中子星质量的影响。 显示英文摘要

摘要： We show that observations of X-ray pulsing from SAX J1808.4-3658 place a firm upper limit of 13.8 m^{1/3} km on the radius of the neutron star, where m is its mass in solar units. The limit is independent of distance or assumptions about the magnetospheric geometry, and could be significantly tightened by observations of the pulsations in the near future. We discuss the implications for the equation of state and the possible neutron star mass.