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Physical parameters of both the mass donor and compact object can beconstrained in X-ray binaries with well-defined eclipses, as our survey ofwind-fed supergiant X-ray binaries (SGXBs) IGR J16393-4643, IGR J16418-4532,IGR J16479-4514, IGR J18027-2016 and XTE J1855-026 reveals. Using the orbitalperiod and Kepler's third law, we express the eclipse half-angle in terms ofradius, inclination angle and the sum of the masses. Pulse-timing and radialvelocity curves can give masses of both the donor and compact object as in thecase of the "double-lined" binaries IGR J18027-2016 and XTE J1855-026. Theeclipse half angles are 15 (+3,-2), 31.7 (+0.7,-0.8), 32 +/- 2, 34 +/- 2 and33.6 +/- 0.7 degrees for IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGRJ18027-2016 and XTE 1855-026, respectively. In wind-fed systems, the primarynot exceeding the Roche-lobe size provides an upper limit on system parameters.In IGR J16393-4643, spectral types of B0 V or B0-5 III are found to beconsistent with the eclipse duration and Roche-lobe, but the previouslyproposed donor stars in IGR J16418-4532 and IGR J16479-4514 were found to beinconsistent with the Roche-lobe size. Stars with spectral types O7.5 I andearlier are possible. For IGR J18027-2016, the mass and radius of the donorstar lie between 18.6--19.4 $M_\odot$ and 17.4--19.5 $R_\odot$. We constrainthe neutron star mass between 1.37--1.43 $M_\odot$. We find the mass and radiusof the donor star in XTE J1855-026 to lie between 19.6--20.2 $M_\odot$ and21.5--23.0 $R_\odot$. The neutron star mass was constrained to 1.77--1.82$M_\odot$. Eclipse profiles are asymmetric in IGR J18027-2016 and XTEJ1855-026, which we attribute to accretion wakes.

Probing the Masses and Radii of Donor Stars in Eclipsing X-ray Binaries with the Swift Burst Alert Telescope