2004AJ....127..469S

A new ephemeris has been determined for the supersoft X-ray binary CAL 83 using MACHO Project photometry. With an improved orbital period of 1.047568 days, it is now possible to phase together photometric and spectroscopic data obtained over the past two decades with new far-ultraviolet spectra taken with the Far Ultraviolet Spectroscopic Explorer. We discuss the properties of the orbital and long-term optical light curves, as well as the colors, of CAL 83. In the far-ultraviolet, the only well-detected stellar feature is emission from the O VI resonance doublet. The radial velocity of this emission appears to differ from that of He II in the optical region, although we only have partial phase coverage for the O VI line. The FUSE continuum variations are similar to the optical light curve in phase and amplitude.