IGR J11305-6256 is one of the numerous sources discovered through the INTEGRAL scan of the Galactic Plane .
Thanks to the Swift-BAT survey , that allows the frequent sampling of any sky region , we have discovered in the hard X-ray emission of this source a modulation with a period of 120.83 d. The significance of this periodic modulation is \sim 4 standard deviations in Gaussian statistics .
We interpret it as the orbital period of the binary system .
We derive an orbital separation between IGR J11305-6256 and its companion star of \sim 286 R _ { \odot } corresponding to \sim 19 times the radius of the companion star .
The broadband XRT-BAT ( 0.3 - 150 keV ) spectrum is described either by the sum of a black-body and a cut-off power-law or by a partially absorbed cut-off power-law .
The temporal and spectral characteristics of the source indicate its possible association with the class of persistent , but faint , Be X-ray binary systems .