  Timing analysis of ~12.4 Ms of INTEGRAL/IBIS data has revealed a period of
51.47 +/- 0.02 days in the supergiant fast X-ray transient source XTE
J1739-302/IGR J17391-3021 that can be interpreted as an orbital period. An
outburst history showing 35 epochs of activity has been produced, showing X-ray
outbursts throughout the orbit of XTE J1739-302. Possible indications of an
enhanced equatorial density region within the supergiant stellar wind are
present in the phase-folded lightcurve. It is found that many orbital
configurations are possible within this system with eccentricities of up to e
~0.8 valid.
