What is the nature of RX J0720.4-3125?


RX J0720.4-3125 has recently been identified as a pulsating soft X-ray source in the ROSAT all-sky survey with a period of 8.391 s. Its spectrum is well characterized by a black-body with a temperature of 8×1058 \times 10^5 K. We propose that the radiation from this object is thermal emission from a cooling neutron star. For this black-body temperature we can obtain a robust estimate of the object's age of 3×105\sim 3 \times 10^5 yr, yielding a polar field 1014\sim 10^{14} G for magnetic-dipole spin down and a value of P˙{\dot P} compatible with current observations.Comment: 4 pages, 1 figures, to appear in Monthly Notice

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    Last time updated on 05/06/2019