Far-ultraviolet spectra of LMC X-3 were taken covering photometric phases 0.47–0.74 in the 1.7 day orbital period of the black hole binary (phase zero being superior conjunction of the X-ray source). The continuum is faint and flat but appears to vary significantly during the observations. Concurrent RXTE/ASM observations show the system was in its most luminous X-ray state during the Far Ultraviolet Spectroscopic Explorer (FUSE) observations. The far-UV spectrum contains strong terrestrial airglow emission lines, while the only stellar lines clearly present are emissions from the O VI resonance doublet. Their flux does not change significantly during the FUSE observations. These lines are modeled as two asymmetric profiles, including the local ISM absorptions due to C II and possibly O VI. Velocity variations of O VI emission are consistent with the orbital velocity of the black hole and provide a new constraint on its mass.
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机译：LMC X-3的远紫外光谱是在黑洞双星的1.7天轨道周期（零相是X射线源的优越结合）的1.7天轨道周期内测得的0.47-0.74光度相。连续体是微弱且平坦的，但是在观察过程中似乎有很大变化。并发RXTE / ASM观测显示，在远紫外光谱浏览器（FUSE）观测期间，系统处于其最亮的X射线状态。远紫外线光谱包含很强的地面气辉发射线，而唯一清晰可见的恒星线是O VI共振双峰的发射。在FUSE观测期间，它们的通量没有明显变化。这些线被建模为两个不对称分布，包括由于C II以及可能的O VI引起的局部ISM吸收。 O VI发射的速度变化与黑洞的轨道速度一致，并为其质量提供了新的约束。
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