2015ApJ...808..140C

Physical parameters of both the mass donor and compact object can be constrained in X-ray binaries with well-defined eclipses, as our survey of wind-fed supergiant X-ray binaries IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGR J18027-2016, and XTE J1855-026 reveals. Using the orbital period and Kepler's third law, we express the eclipse half-angle in terms of radius, inclination angle, and the sum of the masses. Pulse-timing and radial velocity curves can give masses of both the donor and compact object as in the case of the ''double-lined'' binaries IGR J18027-2016 and XTE J1855-026. The eclipse half angles are 15_–2⁺³, 31.7_–0.8^+0.7, 32±2,34±2, and 33.6±0.7 degrees for IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGR J18027-2016, and XTE 1855-026, respectively. In wind-fed systems, the primary not 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 be consistent with the eclipse duration and Roche-lobe, but the previously proposed donor stars in IGR J16418-4532 and IGR J16479-4514 were found to be inconsistent with the Roche-lobe size. Stars with spectral types O7.5 I and earlier are possible. For IGR J18027-2016, the mass and radius of the donor star lie between 18.6-19.4 M_☉ and 17.4-19.5 R_☉. We constrain the neutron star mass between 1.37 and 1.43 M_☉.We find the mass and radius of the donor star in XTE J1855-026 to lie between 19.6-20.2 M_☉ and 21.5-23.0 R_☉. The neutron star mass was constrained to 1.77-1.82 M_☉. Eclipse profiles are asymmetric in IGR J18027-2016 and XTE J1855-026, which we attribute to accretion wakes.