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Observations of Scorpius X-1 with IUE - Ultraviolet results from a multiwavelength campaign

DOI

55

Citations

0

References

1991

Year

S. D. Vrtilek, W. Penninx, J. C. Raymond, F. Verbunt, P. Hertz, K. Wood, W. H. G. Lewin, K. Mitsuda
The Astrophysical Journal

Abstract

IUE UV results are presented for the low-mass X-ray binary Sco X-1. Models that predict UV continuum emission from the X-ray-heated surface from the companion star and from an X-ray illuminated accretion disk are adjusted for parameters intrinsic to Sco X-1, and fitted to the data. X-ray heating is found to be the dominant source of UV emission; the mass-accretion rate increases monotonically along the 'Z-shaped' curve in an X-ray color-color diagram. UV emission lines from He, C, N, O, and Si were detected; they all increase in intensity from the HB to the FB state. A model in which emission lines are due to outer-disk photoionization by the X-ray source is noted to give good agreement with line fluxes observed in each state.