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

Abstract

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 (SGXBs) 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 (+3,-2), 31.7 (+0.7,-0.8), 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 $M_{\odot }$ and 17.4--19.5 $R_{\odot }$. We constrain the neutron star mass between 1.37--1.43 $M_{\odot }$. We find the mass and radius of the donor star in XTE J1855-026 to lie between 19.6--20.2 $M_{\odot }$ and 21.5--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 XTE J1855-026, which we attribute to accretion wakes.

33 pages, 21 figures, accepted for publication in The Astrophysical Journal

References in corpus (16)

• UBVJHK synthetic photometry of Galactic O stars
• The ephemeris, orbital decay, and masses of 10 eclipsing HMXBs
• Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. I. The nature of the companion star
• Statistical properties of a sample of periodically variable B-type supergiants - Evidence for opacity-driven gravity-mode oscillations
• Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. II. The environment of the companion star
• Unveiling the nature of INTEGRAL objects through optical spectroscopy. VI. A multi-observatory identification campaign
• Unveiling the nature of six HMXBs through IR spectroscopy
• Distribution of High-Mass X-ray Binaries in the Milky Way
• The 1 - 50 keV spectral and timing analysis of IGR J18027-2016: an eclipsing, high mass X-ray binary
• Monitoring Supergiant Fast X-ray Transients with Swift. Results from the first year
• Orbital Parameters for the X-ray Pulsar IGR J16393-4643
• Orbital phase resolved spectroscopy of GX 301-2 with MAXI
• Chandra observations of five INTEGRAL sources: new X-ray positions for IGR J16393-4643 and IGR J17091-3624
• A Suzaku view of IGR J16393-4643
• Fundamental properties of High-Mass X-ray Binaries
• Probing the Mysteries of the X-Ray Binary 4U 1210-64 with ASM, PCA, MAXI, BAT and Suzaku

Cited by in corpus (19)

• X-ray Emissions from Accreting White Dwarfs: a Review
• Advances in Understanding High-Mass X-ray Binaries with INTEGRAL and Future Directions
• Distances to Galactic X-ray Binaries with Gaia DR2
• X-ray reprocessing: Through the eclipse spectra of high mass X-ray binaries with XMM-Newton
• NuSTAR discovery of a cyclotron line in the accreting X-ray pulsar IGR J16393-4643
• SFXTs versus classical SgXBs: Does the difference lie in the companion wind?
• Orbital evolution and search for eccentricity and apsidal motion in the eclipsing HMXB 4U 1700-37
• On the possibility of disk-fed formation in supergiant high-mass X-ray binaries
• Diverse Long-Term Variability of Five Candidate High-Mass X-ray Binaries from Swift Burst Alert Telescope Observations
• XMM-Newton and Swift observations of supergiant high mass X-ray binaries
• Superorbital Modulation in the High-Mass X-ray Binary 4U 1538-52, and Possible Modulation in IGR J16393-4643
• Monitoring clumpy wind accretion in supergiant fast X-ray transients with XMM-Newto
• Young Stellar Populations in MYStIX Star Forming Regions: Candidate Protostars
• Probing clumpy wind accretion in IGR J18027-2016 with XMM-Newton
• Investigating the superorbital modulations in 4U 1909+07, IGR J16418-4532 and IGR J16479-4514 with Swift XRT, BAT and NuSTAR observations
• The Orbital Parameters of the Eclipsing High-Mass X-ray Binary Pulsar IGR J16493-4348 from Pulsar Timing
• Dust-scattering halo and giant hard X-ray flare from the Supergiant Fast X-ray Transient IGR J16479-4514 investigated with XMM-Newton and INTEGRAL
• Stellar wind structures in the eclipsing binary system IGR J18027-2016
• Wind accretion onto compact objects