FIVE WIND-ACCRETING SUPERGIANT HIGH-MASS X-RAY BINARIES ARE NOW KNOWN TO EXHIBIT SUPERORBITAL PERIODS. UNLIKE SYSTEMS THAT POSSESS PERSISTENT ACCRETION DISKS THE CAUSE OF THIS MODULATION IS UNKNOWN ALTHOUGH SEVERAL MODELS HAVE BEEN PROPOSED. WE WERE AWARDED NUSTAR TIME ON ONE OF THESE SYSTEMS (IGR J16493-4348) IN CYCLE 1 TO COMPARE SUPERORBITAL MAXIMUM AND MINIMUM. SURPRISINGLY WE SEE DIFFERENCES FROM AN RXTE STUDY OF THE SUPERORBITAL MODULATION IN 2S 0114+650. WE NOW REQUEST NUSTAR OBSERVATIONS AT SUPERORBITAL MAXIMUM AND MINIMUM OF THE THREE OTHER KNOWN MEMBERS OF THIS CLASS SO WE CAN DETERMINE GLOBAL MODULATION PROPERTIES AND DISENTANGLE THE EFFECTS OF INCLINATION ANGLE AND ORBITAL PERIOD. DETERMINING THE SUPERORBITAL MECHANISM MAY YIELD INSIGHTS INTO SUPERGIANT WIND PROPERTIES.

University Of Maryland Baltimore County, Baltimore MD

Investigators