We report the association of the INTEGRAL source IGR J18027-2016 with the BeppoSAX source SAX J1802.7-2017 .
IGR J18027-2016 is seen to be a weak , persistent source by the IBIS/ISGRI instrument on board INTEGRAL with an average source count rate of 0.55 counts s ^ { -1 } ( \sim 6.1 mCrab ) in the 20-40 keV band .
Timing analysis performed on the ISGRI data identifies an orbital period of 4.5696 \pm 0.0009 days and gives an ephemeris of mid-eclipse as , T _ { mid } = 52931.37 \pm 0.04 MJD .
Re-analysis of archival BeppoSAX data has provided a mass function for the donor star , f ( m ) = 16 \pm 1 M _ { \sun } and a projected semimajor axis of a _ { x } \sin { i } = 68 \pm 1 lt-s. We conclude that the donor is an OB-supergiant with a mass of 18.8–29.3 M _ { \sun } and a radius of 15.0–23.4 R _ { \sun } .
Spectra obtained by XMM-Newton and ISGRI indicate a high hydrogen column density of N _ { H } = 6.8 \times 10 ^ { 22 } cm ^ { -2 } , which suggests intrinsic absorption .
The source appears to be a high mass X-ray binary with the neutron star emitting X-rays through wind-fed accretion while in an eclipsing orbit around an OB-supergiant .