71 research outputs found
Radial-velocity curves and theoretical spectral-line profiles of the components of low-mass close X-ray binary systems
We present the results of calculations of theoretical absorption-line profiles and radial-velocity curves for optical components in X-ray binary systems. Tidal distortion of the optical star and X-ray heating by incident radiation from the relativistic object are taken into account. An emission component forms whose intensity varies with orbital phase in the absorption-line profile in the presence of significant X-ray heating. As a result, the width of the line decreases rather than increases at quadrature. The line profiles and equivalent widths and the radial-velocity curves depend substantially on the parameters of the binary systems. This provides the possibility of directly determining component masses and orbital inclinations from high-resolution spectroscopic observations of X-ray binary systems. © 2005 Pleiades Publishing, Inc
A Spectroscopic Study of Mass Outflows in the Interacting Binary RY Scuti
The massive interacting binary RY Scuti is an important representative of an
active mass-transferring system that is changing before our eyes and which may
be an example of the formation of a Wolf-Rayet star through tidal stripping.
Utilizing new and previously published spectra, we present examples of how a
number of illustrative absorption and emission features vary during the binary
orbit. We identify spectral features associated with each component, calculate
a new, double-lined spectroscopic binary orbit, and find masses of 7.1 +/- 1.2
M_sun for the bright supergiant and 30.0 +/- 2.1 M_sun for the hidden massive
companion. Through tomographic reconstruction of the component spectra from the
composite spectra, we confirm the O9.7 Ibpe spectral class of the bright
supergiant and discover a B0.5 I spectrum associated with the hidden massive
companion; however, we suggest that the latter is actually the spectrum of the
photosphere of the accretion torus immediately surrounding the massive
companion. We describe the complex nature of the mass loss flows from the
system in the context of recent hydrodynamical models for beta Lyr, leading us
to conclude RY Scuti has matter leaving the system in two ways: 1) a bipolar
outflow from winds generated by the hidden massive companion, and 2) mass from
the bright O9.7 Ibpe supergiant flowing from the region near the L2 point to
fill out a large, dense circumbinary disk. This circumbinary disk (radius ~ 1
AU) may feed the surrounding double-toroidal nebula (radius ~ 2000 AU).Comment: 41 pages with 7 tables and 11 figures, accepted to Ap
The mass of the compact object in the low-mass X-ray binary 2S 0921-630
We interpret the observed radial-velocity curve of the optical star in the low-mass X-ray binary 2S 0921-630 using a Roche model, taking into account the X-ray heating of the optical star and screening of X-rays coming from the relativistic object by the accretion disk. Consequences of possible anisotropy of the X-ray radiation are considered. We obtain relations between the masses of the optical and compact (X-ray) components, m v and m x , for orbital inclinations i = 60°, 75°, and 90°. Including X-ray heating enabled us to reduce the compact object's mass by ∼0.5-1 M ⊙, compared to the case with no heating. Based on the K0III spectral type of the optical component (with a probable mass of m v ≈ 2.9 M ⊙), we concluded that m x ≈ 2.45-2.55 M ⊙ (for i = 75°-90°). If the K0III star has lost a substantial part of its mass as a result of mass exchange, as in the V404 Cyg and GRS 1905+105 systems, and its mass is m v ≈ 0.65-0.75 M ⊙, the compact object's mass is close to the standard mass of a neutron star, m x ≈ 1.4 M ⊙ (for i = 75°-90°). Thus, it is probable that the X-ray source in the 2S 0921-630 binary is an accreting neutron star. © Pleiades Publishing, Inc., 2006
The mass of the compact object in the X-ray binary her X-1/HZ her
We have obtained the first estimates of the masses of the components of the Her X-1/HZ Her X-ray binary system taking into account non-LTE effects in the formation of the H γ absorption line: m x = 1.8 M⊙ and mv = 2.5 M⊙. These mass estimates were made in a Roche model based on the observed radial-velocity curve of the optical star, HZ Her. The masses for the X-ray pulsar and optical star obtained for an LTE model lie are m x = 0.85 ± 0.15 M⊙ and mv = 1.87 ± 0.13 M⊙. These mass estimates for the components of Her X-1/HZ Her derived from the radial-velocity curve should be considered tentative. Further mass estimates from high-precision observations of the orbital variability of the absorption profiles in a non-LTE model for the atmosphere of the optical component should be made. © 2008 Pleiades Publishing, Ltd
INTEGRAL observations of SS433, a supercritically accreting microquasar with hard spectrum
Observations of SS433 by INTEGRAL carried out in March -- May 2003 are
presented. SS433 is evidently detected on the INTEGRAL images of the
corresponding sky region in the energy bands 25-50 and 50-100 keV. The
precessional variability of the hard X-ray flux is clearly seen. The X-ray
eclipse caused by the binary orbital motion is also detected. A possible origin
of the hard continuum is briefly discussed.Comment: 5 pages, 6 figures. Accepted to A&A INTEGRAL special volum
The mass of the black hole in the X-ray binary LMC X-1
© 2016, Pleiades Publishing, Ltd.A dynamical estimate of the mass of the black hole in the LMC X-1 binary system is obtained in the framework of a Roche model for the optical star, based on fitting of the He I 4471 Å and He II 4200 Å absorption lines assuming LTE. The mass of the black hole derived from the radial-velocity curve for the He II 4200 Å line is mx = 10.55 M⊙, close to the value found earlier based on a model with two point bodies [1]
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