Timing analysis of \sim 12.4 Ms of INTEGRAL /IBIS data has revealed a period of 51.47 \pm 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 \sim 0.8 valid .