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1.
Suhail Gumaan Masda Mashhoor Ahmed Al-Wardat Jiyaulla Khan Moula Khan Pathan 《天文和天体物理学研究(英文版)》2018,(6)
The best physical and geometrical parameters of the main sequence close visual binary system(CVBS), HIP 105947, are presented. These parameters have been constructed conclusively using Al-Wardat's complex method for analyzing CVBSs, which is a method for constructing a synthetic spectral energy distribution(SED) for the entire binary system using individual SEDs for each component star. The model atmospheres are in its turn built using the Kurucz(ATLAS9) line-blanketed plane-parallel models. At the same time, the orbital parameters for the system are calculated using Tokovinin's dynamical method for constructing the best orbits of an interferometric binary system. Moreover, the mass-sum of the components, as well as the ?θ and ?ρ residuals for the system, is introduced. The combination of Al-Wardat's and Tokovinin's methods yields the best estimations of the physical and geometrical parameters. The positions of the components in the system on the evolutionary tracks and isochrones are plotted and the formation and evolution of the system are discussed. 相似文献
2.
H.A. Sabat H.M. Al-Naimiy I.A. Barghouthi M.A.S. Al-Wardat 《Astrophysics and Space Science》1998,260(3):347-357
In this paper, the standard model of X-ray binaries was used in synthesizing light-curves of eclipsing X-ray binaries. Two
moderated approaches were introduced in this regard; the first concerns the method of solution of the Roche Model's basic
equation, where, instead of using series solutions as developed by Kopal, the Newton-Raphson method was utilized to solve
it, after changing it into an eighth-degree polynomial equation, which proved to be more precise, and yet, more efficient.
The second approach concerns the development of a new phenomenological model to account for X-ray reflection, and heating
of the optical star. Our model was successfully applied to HZ-Her/Her X-1.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
M. A. Al-Wardat H. Al-Naimiy A. Taani A. Khasawneh O. Al-Banawi H. S. Widyan 《Astrophysical Bulletin》2014,69(3):325-329
Modified physical and geometric parameters for the eclipsing x-ray binary system Cen X-3 are presented. The parameters were estimated by comparing synthetic photometric light curves with the observed ones in an iterative method until the best fit was achieved. The synthetic light curves were constructed in accordance with the Roche model, since Cen X-3 is likely to be powered by Roche-lobe overflow. We focused on the phenomenon of x-ray heating of the side of the optical component facing the compact object. The parameters and present status of this work are briefly discussed. 相似文献
4.
The study of the chemical composition of stars and galaxies is a key topic for understanding their origin and evolution. In this study, we present the results of the calculation of solar abundances of the isotopes 1H, 4He, 12C, 14N, 15O, 16O, 17O, and 18O during the four phases of the solar life: hydrogen burning, onset of rapid growth and red giant, helium burning and helium exhaustion. The open source package “NucNet Tools” from the Webnucleo Group in Clemson University, SC, USA was used for this purpose. The results for all isotopes are listed in tables for future use. Abundances found, globally, agree fairly well with those predicted in the literature. Results obtained for the last two phases have no equivalents elsewhere. 相似文献
5.
M.A.S. Al-Wardat H.M. Al-Naimiy I.A. Barghouthi H.A. Sabat 《Astrophysics and Space Science》1998,260(3):335-345
A contribution to the theoretical analysis of eclipsing x-ray binary systems and the calculation of physical and geometrical
elements, are represented. The principle of this work is to make fitting between the observational light curve and the synthetic
light curve built up in accordance with the Roche model, and to consider the elements of the best fitting as new elements.
This method were applied to three systems, there are:
(i) HZ Herculis (Hercules X-1).
(ii) Krzemenski's star (Centaurus X-3).
(iii) HD 77851 (Vela X-1).
Finally, the mass-luminosity relation and the H-R diagram for the optical components of the three systems, have been plotted
and studied.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Ali Taani Shigeyuki Karino Liming Song Mashhoor Al-Wardat Awni Khasawneh Mohammad K.Mardini 《天文和天体物理学研究(英文版)》2019,(1)
We consider the existence of a neutron star magnetic field by the detected cyclotron lines. We collected data on nine sources of high-mass X-ray binaries with supergiant companions as a test case for our model, to demonstrate their distribution and evolution. The wind velocity, spin period and magnetic field strength are studied under different mass loss rates. In our model, correlations between mass-loss rate and wind velocity are found and can be tested in further observations. We examine the parameter space where wind accretion is allowed, avoiding the barrier of rotating magnetic fields, with robust data on the magnetic field of neutron stars. Our model shows that most sources(six of nine systems) can be fed by the wind with relatively slow velocity, and this result is consistent with previous predictions. In a few sources,our model cannot fit the standard wind accretion scenario. In these peculiar cases, other scenarios(disk formation, partial Roche lobe overflow) should be considered. This would provide information about the evolutionary tracks of various types of binaries, and thus exhibit a clear dichotomy behavior in wind-fed X-ray binary systems. 相似文献
7.
M. A. Al-Wardat 《Astrophysical Bulletin》2008,63(4):361-365
The synthetic magnitudes and color indices of 46 speckle interferometric stars have been computed depending on their observational spectral energy distributions. The Strömgren vby and Tycho BV passbands have been used to calculate magnitudes of the systems. These data when combined with the magnitude differences of the sub-components from speckle interferometry observations will allow the finding of the parameters of the individual components. These parameters will improve our knowledge about binary system formation and evolution. 相似文献
8.
M. A. Al-Wardat Yu. Yu. Balega V. V. Leushin N. A. Yusuf A. A. Taani K. S. Al-Waqfi S. Masda 《Astrophysical Bulletin》2014,69(1):58-66
Atmospheric modeling is used to build synthetic spectral energy distributions (SEDs) for the individual components of the speckle interferometric binary system HD375. These synthetic SEDs are combined together for the entire system and compared with its observed SED in an iterative procedure to achieve the best fit. Kurucz blanketed models and the measurements of magnitude differences were used to build these SEDs. The input physical parameters for building these best fitted synthetic SEDs represent adequately enough properties of the system. These parameters are: T eff a = 6100 ± 50 K, T eff b = 5940 ± 50 K, log g a = 4.01 ± 0.10, log g b = 3.98 ± 0.10, R a = 1.93 ± 0.20R ⊙, R b = 1.83 ± 0.20R ⊙, M v a = 3 · m 26 ± 0.40, M v b = 3 · m 51 ± 0.50, L a = 4.63 ± 0.80 L ⊙, and L b = 3.74 ± 0.70 L ⊙, in accordance with the new estimated parallax π = 12.02 ± 0.60 mas. A modified orbit of the system is built and compared with earlier orbits, and the masses of the two components are calculated as M a = 1.35M ⊙ and M b = 1.25M ⊙. Based on the estimated physical and geometrical parameters of the system, which are confirmed by synthetic photometry, we suggest that the two components are evolved subgiant (F8.5 IV and G0 IV) stars with the age of 3.5 Gyr, formed by fragmentation. 相似文献
9.
The physical and geometrical parameters of the individual components of the binary system Hip11253 (HD14874) are estimated. We used the method described in previous papers, which consists in getting the best fit between the entire observational spectral energy distribution of the system and the synthetic ones, created from model atmospheres. The parameters of the individual components of the system are derived as: T eff a = 6030 ± 100 K, T eff b = 4470 ± 130 K, log g a = 4.27 ± 0.13, log g b = 4.04 ± 0.13, R a = 1.22 ± 0.09R⊙, R b = 1.32 ± 0.20R⊙, with the G0 and K4.5 spectral types for the primary and secondary components, respectively. The synthetic magnitudes of both components were calculated using the Johnson-Cousins, Strömgren, and Tycho photometrical systems. Finally the formation and evolution of the system was discussed. 相似文献
10.
Suhail G. Masda Mashhoor A. Al-Wardat J. M. Pathan 《Journal of Astrophysics and Astronomy》2018,39(5):58
We present the stellar parameters of the individual components of the two old close binary systems HIP 14075 and HIP 14230 using synthetic photometric analysis. These parameters are accurately calculated based on the best match between the synthetic photometric results within three different photometric systems with the observed photometry of the entire system. From the synthetic photometry, we derive the masses and radii of HIP 14075 as \({\mathcal {M}}^A=0.99\pm 0.19 \mathcal {M_\odot }\), \(R_{A}=0.877\pm 0.08 R_\odot \) for the primary and \({\mathcal {M}}^B=0.96\pm 0.15 \mathcal {M_\odot }\), \(R_{B}=0.821\pm 0.07 R_\odot \) for the secondary, and of HIP 14230 as \({\mathcal {M}}^A=1.18\pm 0.22 \mathcal {M_\odot }\), \(R_{A}=1.234\pm 0.05 R_\odot \) for the primary and \({\mathcal {M}}^B=0.84\pm 0.12 \mathcal {M_\odot }\) , \(R_{B}=0.820\pm 0.05 R_\odot \) for the secondary. Both systems depend on Gaia parallaxes. Based on the positions of the components of the two systems on a theoretical Hertzsprung–Russell diagram, we find that the age of HIP 14075 is \(11.5\pm 2.0\) Gyr and of HIP 14230 is \(3.5\pm 1.5\) Gyr. Our analysis reveals that both systems are old close binary systems (\(\approx > 4\) Gyr). Finally, the positions of the components of both the systems on the stellar evolutionary tracks and isochrones are discussed. 相似文献