Wind Accretion and Binary Evolution of the Microquasar LS 5039

Abstract

There is much evidence to suggest that stellar wind capture, rather than Roche lobe overflow, serves as the accretion mechanism onto the compact secondary object in the massive X-ray binary LS 5039. The lack of significant emission combined with only a modest X-ray flux provide observational evidence that no large-scale mass transfer is occurring (consistent with our estimate of the radius of the O6.5 V((f)) optical star that is smaller than its critical Roche radius). Here we determine the mass loss rate of the optical star from the broad, residual emission in the H-alpha profile. Using a stellar wind accretion model for a range in assumed primary mass, we compute the predicted X-ray luminosity for the system. We compare our results to the observed X-ray luminosity to determine the mass of the compact object for each case. The companion appears to be a neutron star with a mass between 1 and 3 solar masses. With our new constraints on the masses of both components, we discuss their implications on the evolution of the system before and after the supernova event that created the compact companion. The binary experienced significant mass loss during the supernova, and we find that the predictions for the resulting runaway velocity agree well with the observed peculiar space velocity. LS 5039 may be the fastest runaway object among known massive X-ray binaries.

submitted to ApJL

References in corpus (4)

• Discovery of a High-Energy Gamma-Ray-Emitting Persistent Microquasar
• Formation of contact in massive close binaries
• Modelling the orbital modulation of ultraviolet resonance lines in high-mass X-ray binaries
• High-mass X-ray binaries and OB-runaway stars

Cited by in corpus (13)

• Gamma-ray binaries and related systems
• Gamma-ray binaries: pulsars in disguise ?
• Photon-Photon Absorption of Very High Energy Gamma-Rays from Microquasars: Application to LS 5039
• The N Enrichment and Supernova Ejection of the Runaway Microquasar LS 5039
• A numerical model for the gamma-ray emission of the microquasar LS 5039
• The Low X-Ray State of LS 5039 / RX J1826.2-1450
• Multiwavelength monitoring of BD+53 2790, the optical counterpart to 4U~2206+54
• Exploring the connection between the stellar wind and the non-thermal emission in LS 5039
• Long-term X-ray variability of the microquasar system LS 5039/RX J1826.2-1450
• On the origin of LS 5039 and PSR J1825-1446
• X-ray absorption and occultation in LS 5039
• Constraints on the Geometry of the VHE Emission in LS 5039 from Photon-Photon Deabsorption
• Optical polarimetric observations of the microquasar LS 5039