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arXiv · astro-ph/9801038

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

Jeremy S. Heyl·Lars Hernquist
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Abstract

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 $8 \times 10^5$ 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 $\sim 3 \times 10^5$ yr, yielding a polar field $\sim 10^{14}$ G for magnetic-dipole spin down and a value of ${\dot P}$ compatible with current observations.

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Jeremy S. Heyl, Lars Hernquist. 1998-01-06. What is the nature of RX J0720.4-3125?. https://doi.org/10.1046/j.1365-8711.1998.01799.x

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