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A limit-cycle model for the binary supersoft X-ray source RX J0513.9-6951

K. Reinsch·A. van Teeseling·A. R. King·K. Beuermann
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Abstract

We present new results of our X-ray monitoring of the transient binary supersoft X-ray source RX J0513.9-6951 in the LMC and of our re-analysis of optical light curves obtained during the MACHO project. We have covered a complete X-ray outburst cycle with the ROSAT HRI detector. From the amplitude and timescale of the soft X-ray variability, tight limits are derived for the temporal behaviour of the white-dwarf radius and the effective temperature of its envelope. A limit-cycle model is proposed to explain the observed optical and X-ray variability, the characteristic timescales of the durations of the X-ray on and off states, and those of the transitions between both states. Our observations confirm that the radius changes of the white-dwarf envelope occur on the Kelvin-Helmholtz timescale. The duration of the X-ray on and off states is compatible with the viscous timescales of the inner and outer accretion disk, respectively.

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K. Reinsch, A. van Teeseling, A. R. King, K. Beuermann. 2000-01-06. A limit-cycle model for the binary supersoft X-ray source RX J0513.9-6951. https://arxiv.org/abs/astro-ph/0001081

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