Identification of the Mass Donor Star's Spectrum in SS 433

Abstract

We present spectroscopy of the microquasar SS 433 obtained near primary eclipse and disk precessional phase Psi = 0.0, when the accretion disk is expected to be most ``face-on''. The likelihood of observing the spectrum of the mass donor is maximized at this combination of orbital and precessional phases since the donor is in the foreground and above the extended disk believed to be present in the system. The spectra were obtained over four different runs centered on these special phases. The blue spectra show clear evidence of absorption features consistent with a classification of A3-7 I. The behavior of the observed lines indicates an origin in the mass donor. The observed radial velocity variations are in anti-phase to the disk, the absorption lines strengthen at mid-eclipse when the donor star is expected to contribute its maximum percentage of the total flux, and the line widths are consistent with lines created in an A supergiant photosphere. We discuss and cast doubt on the possibility that these lines represent a shell spectrum rather than the mass donor itself. We re-evaluate the mass ratio of the system and derive masses of 10.9 +/- 3.1 Msun and 2.9 +/- 0.7 Msun for the mass donor and compact object plus disk, respectively. We suggest that the compact object is a low mass black hole. In addition, we review the behavior of the observed emission lines from both the disk/wind and high velocity jets.

submitted to ApJ, 24 pages, 7 figures

References in corpus (9)

• Neutron Star Mass Measurements. I. Radio Pulsars
• The Optical Light Curves of Cygnus X-2 (V1341 Cyg) and the Mass of its Neutron Star
• The mass of the neutron star in Vela X-1 and tidally induced non-radial oscillations in GP Vel
• The mass of the neutron star in Vela X-1
• The mass of the neutron star in Cyg X-2 (V1341 Cyg)
• Twenty Years of Timing SS433
• Spectral Components of SS 433
• The Evolutionary Status of SS433
• The Spectrum of the Mass Donor Star in SS 433

Cited by in corpus (46)

• The Nature of SS433 and the Ultraluminous X-ray Sources
• Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest
• Ultraluminous X-Ray Sources
• A catalogue of high-mass X-ray binaries in the Galaxy: from the INTEGRAL to the Gaia era
• The Distance to SS433/W50 and its Interaction with the ISM
• Spectroscopic Observations of the Mass Donor Star in SS 433
• When Microquasar Jets and Supernova Collide: Hydrodynamically Simulating the SS433-W50 Interaction
• Production of gamma rays and neutrinos in the dark jets of the microquasar SS433
• Cygnus X-3 and the problem of the missing Wolf-Rayet X-ray binaries
• Subaru and Gemini Observations of SS 433: New Constraint on the Mass of the Compact Object
• Detection of persistent gamma-ray emission toward SS433/W50
• The Nature of the Compact X-ray Source in Supernova Remnant RCW 103
• SS 433 : a phenomenon imitating a Wolf-Rayet star
• Determining the Nature of the SS 433 Binary Using an X-ray Spectrum During Eclipse
• Magnetic Field Upper Limits for Jet Formation
• On masses of the components in SS433
• SS433: a massive X-ray binary at advanced evolutionary stage
• Discovery of orbital Eccentricity and Evidence for orbital Period Increase of SS433
• INTEGRAL observations of SS433: system's parameters and nutation of supercritical accretion disk
• Diagnostics of the black hole candidate SS433 with the RXTE
• Astrometric observations of X-ray binaries using very long baseline interferometry
• Monte-Carlo simulations of the broadband X-ray continuum of SS433
• On the Origin of the Absorption Features in SS433
• Multi-wavelength Emission from Galactic Jets: the Case of the Microquasar SS433
• A Study of the Evolution of the Close Binaries Cyg X-3, IC 10 X-1, NGC 300 X-1, SS 433, and M33 X-7 Using the "Scenario Machine"
• Broad band variability of SS433: Accretion disk at work?
• Mass ratio in SS433 revisited
• Peculiar nature of hard X-ray eclipse in SS433 from INTEGRAL observations
• Gamma-rays from SS433: evidence for periodicity
• Interpretation of observations of the circumbinary disk of SS 433
• Diagnostics of Parameters for the X-ray Jets of SS 433 from High-Resolution Chandra Spectroscopy
• An optical spectroscopic and polarimetric study of the microquasar binary system SS 433
• Spatially resolved study of the SS 433/W50 west region with Chandra: X-ray structure and spectral variation of non-thermal emission
• Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope
• Superbroad Component in Emission Lines of SS 433
• Fast optical variability of SS 433
• Black holes at cosmic dawn in the redshifted 21cm signal of HI
• SS 433: Results of a Recent Multi-wavelength Campaign
• Astrophysics in 2005
• On the Formation of SS433
• Arcsecond-Scale X-ray Imaging and Spectroscopy of SS 433 with Chandra HETG
• Spectral and photometric variability of SS 433 observed with XRISM and simultaneous optical and near-infrared telescopes
• The B-Supergiant Components of the Double-Lined Binary HD1383
• Further evidence for natal kick segregation by spectral type in high-mass X-ray binaries
• Simulation-calibrated Bayesian inference for progenitor properties of the microquasar SS 433
• Optical Light Curves of Luminous Eclipsing Black Hole X-ray Binaries