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FUV Spectroscopy of the Supersoft X-ray Binary RX J0513.9-6951

J. B. Hutchings·K. Winter·D. Crampton·A. P. Cowley·P. C. Schmidtke
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Abstract

We have obtained spectroscopy with the Far Ultraviolet Spectroscopic Explorer (FUSE) of the supersoft X-ray binary RX J0513.9-6951 over a complete binary orbital cycle. The spectra show a hot continuum with extremely broad O VI emission and weak Lyman absorptions. He II emission is weak and narrow, while N III and C III emissions are undetected, although lines from these ions are prominent at optical wavelengths. The broad O VI emission and Lyman absorption show radial velocity curves that are approximately antiphased and have semiamplitudes of ~117 +- 40 and 54 +- 10 km/s, respectively. Narrow emissions from He II and O VI show small velocity variations with phasing different from the broad O VI, but consistent with the optical line peaks. We also measure considerable changes in the FUV continuum and O VI emission line flux. We discuss the possible causes of the measured variations and a tentative binary interpretation.

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J. B. Hutchings, K. Winter, D. Crampton, A. P. Cowley, P. C. Schmidtke. 2002-07-30. FUV Spectroscopy of the Supersoft X-ray Binary RX J0513.9-6951. https://doi.org/10.1086/343839

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