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1.
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. 相似文献
2.
Hipparcos photometric data for the massive O-type binary UW CMa were analysed within the framework of the Roche model. Photometric solutions were obtained for five mass ratios in the q = M2/M1 = 0.5–1.5 range. The system is found to be in a contact configuration. Independently of q, the best-fitting model solutions correspond to the orbital inclination i ~ 71° and the temperature of the secondary component T2 ~ 33500 K, at the fixed temperature of the primary T1 = 33750 K. Considering that the spectrum of the secondary is very weak, photometric solutions corresponding to the contact configuration favor the mass ratio q smaller than unity (in which case the luminosity of the secondary is smaller than that of the primary). The absolute parameters of the system are estimated for different values of the mass ratio. 相似文献
3.
M. K. Abubekerov E. A. Antokhina A. M. Cherepashchuk V. V. Shimanskii 《Astronomy Reports》2008,52(5):379-389
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 m v = 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 m v = 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. 相似文献
4.
Five color UBVRI photometric and polarimetric measurements of the eclipsing binary VW Cyg are reported. It is shown that in the primary minimum the luminosity is attenuated (at short wavelengths) even after passage of the second contact. This fact is interpreted as evidence of gaseous structures in the system. The exchange of matter among the system components is also confirmed by the O-C curve constructed from data covering nearly a hundred years. Polarimetric analysis makes it possible to isolate the intrinsic (P=0.030±0.02) and interstellar components of the polarization. The UBVRI light curves of VW Cyg have been resolved. This was done using an algorithm for synthesizing theoretical light curves in the Roche model. Good agreement was obtained between the theoretical curves and observations in the V, R, and I bands, but the observed minimum depths in the U and B bands exceed the theoretical values. This appears to be caused by gas flows in the system. 相似文献
5.
It is shown that the approximation of the complex, tidally distorted shape of a star as a circular disc with local line profiles and a linear limb-darkening law, which is usually applied when deriving equatorial stellar rotation velocities from line profiles, leads to overestimation of the equatorial velocity V rot sin i and underestimation of the component mass ratio q = M x /M v . A formula enabling correction of the effect of these simplifying assumptions on the shape of a star is used to re-determine the mass ratios q and the masses of the black holes M x and visual components M v in low-mass X-ray binary systems containing black holes. Taking into account the tidal–rotational distortion of the stellar shape can significantly increase the mass ratios q = M x /M v , reducing M v , while M x changes only slightly. The resulting distribution of M v attains its maximum near M v ? 0.35M ⊙, in disagreement with the results of population synthesis computations realizing standard models for Galactic X-ray novae with black holes. Possible ways to overcome this inconsistency are discussed. The derived distribution of M x also differs strongly from the mass distribution for massive stars in the Galaxy. 相似文献
6.
Martynova Yu. V. Krupchatnikov V. N. Gochakov A. V. Antokhina O. Yu. 《Izvestiya Atmospheric and Oceanic Physics》2022,58(1):95-109
Izvestiya, Atmospheric and Oceanic Physics - The relationship between the anomalies of the intensity of snow cover formation in Western Siberia (WS) and thermodynamic state of the atmosphere of... 相似文献
7.
O. Yu. Antokhina P. N. Antokhin O. S. Zorkal’tseva E. V. Devyatova 《Russian Meteorology and Hydrology》2017,42(10):644-652
Based on the NCEP/NCAR and ERA-Interim reanalysis archives, we investigated different methods to detect atmospheric blocking events in Western Siberia. Two criteria were studied that are based on calculating meridional gradients of the 500 hPa height and potential temperature at the dynamic tropopause. A situation is considered blocking, when it features a gradient inversion of the investigated characteristics. Additionally, we performed a synoptic analysis of individual blocking events. 相似文献
8.
O. Yu. Antokhina P. N. Antokhin E. V. Devyatova Yu. V. Martynova 《Russian Meteorology and Hydrology》2018,43(3):143-151
This paper studies the long-term variability of frequency of atmospheric blockings over Western Siberia in 1948–2015 based on the data of three reanalysis projects. We revealed a decreasing blocking frequency for eight of twelve months. However, since the estimated trends of blocking frequency are small comparing to the significant amplitude of interannual variations, we proposed to divide the entire studied period into several quasi-decadal intervals that differ both in the amplitude of interannual fluctuations of blocking frequency and in trends. The effect of Western Siberian blockings imposed on synoptic and climatic variability of meteorological parameters in Asia was studied. The study demonstrated that in summer teleconnection patterns in temperature and precipitation fields are of the close sign-alternating structure; this indirectly indicates that in Western Siberia the blocking is a part of a large-scale wave mechanism. Like the Ural blockings, the blockings occurring over Western Siberia affect meteorological characteristics within the East Asian monsoon area. In winter time they contribute to lower surface temperature and decreased precipitation in Southeast Asia. In summer during blocking events over Western Siberia, precipitation increases in the East Asian monsoon area. 相似文献
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10.
Sergey V. Marchenko Gregor Rauw Eleonora A. Antokhina Igor I. Antokhin Dominique Ballereau Jacques Chauville Michael F. Corcoran Rafael Costero Juan Echevarria Thomas Eversberg Ken G. Gayley Gloria Koenigsberger Anatoly S. Miroshnichenko Anthony F. J. Moffat Nidia I. Morrell Nancy D. Morrison Christopher L. Mulliss Julian M. Pittard Ian R. Stevens Jean-Marie Vreux Jean Zorec 《Monthly notices of the Royal Astronomical Society》2000,317(2):333-342
With the objective of investigating the windwind collision phenomenon and supporting contemporaneous X-ray observations, we have organized a large-scale, coordinated optical monitoring campaign of the massive, highly eccentric O9 III+B1 III binary Iota Orionis. Successfully separating the spectra of the components, we refine the orbital elements and confirm the rapid apsidal motion in the system. We also see strong interaction between the components during periastron passage and detect phase-locked variability in the spectrum of the secondary star. However, we find no unambiguous signs of the bow shock crashing on the surface of the secondary, despite the predictions of hydrodynamic simulations. Combining all available photometric data, we find rapid, phase-locked variations and model them numerically, thus restricting the orbital inclination to 50° i 70°. 相似文献