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The visually close binary system HD; Is it a sub-giant binary? Home The visually close binary system HD; Is it a sub-giant binary? Nov 22, - 0. The fate of close encounters between binary stars and binary Oct 29, - lar dynamical processes in the inner triple are accelerated by the presence of the secondary SMBH, leading to an enhance- ment in the overall rate of observable astronomical events.
When the inner triple has a re. Asteroseismology of close binary stars Jan 16, - Tidal forces can, physical parameters of the visually close binary systems hip70973 and hip72479 course, alter the free oscillations excited.
The parameters for the hot and cooler companions have been deter- mined as Mh. Quantitative spectroscopy of close binary stars Aug 23, - In spectral separation techniques radial velocities RVs are input data obtained from another source e. Our observational project on the chemical Evolution of a binary sy. Nonlinear Tides in Close Binary Systems May 29, - slowly rotating solar type stars with either stellar or plan The left hand side of equation 6 describes an uncoupled oscillator.
The terms on the right hand side represent linear d. MK standards of spectral type B. By visual inspection of. The absolute calibrator was. Transparency is crucial in security-critical applications that rely on authoritative information, as it provides a robust mechanism for holding these authorities accountable for their actions. A number of solutions have emerg.
A close-pair binary in a distant triple supermassive black-hole system Jun 24, - A close-pair binary in a distant triple supermassive black- hole system. Fundamental parameters of the close interacting binary HD Jan 19, - Based on the study of the ASAS V-band light curve we determine an improved orbital period of Planetary systems in close binary stars: In this study, our aim is Exoplanet Web site and was thus withdrawn due to a sig- nificant residual drift in. Is the central binary system of the planetary nebula Henize a Oct 25, - We critically discuss the recent observations of the binary system at the center of the bipolar planetary nebula Henize The Close Binary Fraction of Dwarf M Stars Oct 18, - of stars to understand the rate of occurrence of multiple systems in a statistical sense see.
We take this approach in this paper, taking advantage of the enormous numbers of spectroscopi. BoxAqaba, Jordan N. July 10, ; Received; Revised Atmospheric modeling is used to build synthetic spectral energy distributions SEDs for the individual components of the speckle interferometric binary system HD These synthetic SEDs are combined together for the entire system and compared with its observational SED in an iterated procedure to achieve the best fit.
The input physical elements for building these best fitted synthetic SEDs represent adequately enough the elements of the system. Depending on physical parameters of the visually close binary systems hip70973 and hip72479 estimated physical and geometrical elements of the system, which are assured by synthetic photometry, we suggest that the two components are evolved subgiant F8.
Most of these resolved systems are nearby stars that appear as a single star even with the largest groundbased telescopes except when observed using high resolution techniques like speckle interferometry SI [10, 43] and adaptive optics AO [39, 40]. In general, the study of binary stars is the most powerful direct method to correlate stellar theoretical models with the actual observational elements, which is more complicated in the case of VCBSs.
It connects mass determinations with other important elements such as radius, luminosity, and effective temperature and gives a basic check of stellar structure and evolution theory . It also gives a unique way for a thorough investigation of the spectral types and luminosity classes . The only way to estimate these elements is by indirect analysis of the binaries. A method that makes use of Kurucz blanketed models  to build a synthetic spectral energy distribution SED for each component separately, and hence for the entire system.
Then, by comparing this entire synthetic SED with the observational one in an iterated repetition to achieve the best fit between them, one may be able to determine the physical and geometrical elements of the individual components. The method at first used earlier versions of lineblanketed plane-parallel theoretical model atmospheres for F, G, and K-type stars , where it counted only for the hydrogen lines opacities in building the SEDs . The modified physical and geometrical elements for the system using the modified version of the aforementioned method, and the modified orbit of the system depending on latest SI ob- 2 TABLE III: Magnitude difference between the components of the system along with filters used to obtain the observations.
Data from Hipparcos and Tycho Physical parameters of the visually close binary systems hip70973 and hip72479. These information will enhance our knowledge about stellar parameters in general and consequently will help in understanding the formation and evolution mechanisms of stellar binary systems. This value was used as an input to the equations: Hence a spectral energy distribution for each component are built.
Preliminary individual absolute magnitudes were calculated using equation 3, assuming that both components are main sequence stars. One can write : While the last three criteria depend mainly on Tef f and log g, which were fulfilled using: The resulting entire synthetic SED which is built using the preliminary input elements does not coincide with the observational one. Many attempts were made to achieve the best fit between the synthetic SEDs and the observed one. The preliminary calculated set is taken as starting values and an iteration method for the different sets of elements is used.
The best fit is evaluated using to the following criteria: Achieved best fit between the entire observational SED in the continuous spectrum of the system  and the entire synthetic one of the two components built using Kurucz blanketed models .
Doubts in Hipparcos parallax measurements were introduced by . They noted that, in some cases, Hipparcos parallax measurements are distorted by the the orbital motion of the components of binary systems. Therefore, one has to be careful when physical parameters of the visually close binary systems hip70973 and hip72479 these measurements.
The first approach resulted in the following radii: The estimated entire synthetic visual magnitudes according to the parallax of Hipparcos and the radii of  assuming that both components are main sequence stars are higher i. Now, in order to get the exact fit with the observational absolute flux Fig. While the second approach resulted in the following radii and parallax: The estimated parallax obtained by the second approach does not coincide with orbital elements and mass physical parameters of the visually close binary systems hip70973 and hip72479 calculated hereafter in this work see Table Vwhile that given by Hipparcos was acceptable somehow.
Hence, the elements obtained by the first approach represent the system better than those obtained by the second approach, but not the best see section IV. There are seven new points used to modify the orbit of . The preliminary orbit of , and that of  are shown in Fig. The modified orbital elements of the system along with the previous ones are listed in Table V. It shows a good consistency between our estimated period, periastron epoch, semi-major axis and eccentricity and those estimated by , while there are some differences in the inclination, position angle of nodes and the argument of periastron.
MASSES Using the estimated orbital elements, we calculated the total mass of the system in solar masses and the corresponding error are calculated using the following equations: The calculated mass sum using Hipparcos new parallax gives higher value than what would be expected for two stars with physical parameters of the visually close binary systems hip70973 and hip72479 previously estimated physical elements, which is well enhanced by the positions of the two components on the evolutionary tracks.
Another loop of iterated calculations is performed to reach the best fit between the estimated physical parameters and the orbital ones, especially the mass sum, which affected highly by the parallax value.
The best fit Fig. The final physical and geometrical elements of the system are listed in Table VI, which adequately enough represent the elements of the system within the error values of the measured quantities. Positional Fourth Interferometric Epoch Zero points ZPp from  and references there in are adopted. The results of the calculated magnitudes and color indices Johnson-Cousins: Orbital elements of the system , ,  and this work Parameter Balega et al. Relative visual orbit of the system HD; The origin represents the position of the primary component.
The filled circles are the new points used to modify the orbit see Table IV and Hipparcos point is denoted by a star. Physical and geometrical elements of the components of the system. Magnitudes and color indices of the synthetic spectra of the system. Comparison between entire synthetic visible magnitudes and color indices of the system with the entire ones calculated from the observational SED .
The least-square fitting with weights inversely proportional to the squares of the positional measurements observational errors is used to modify the orbit of the system. Hence, the physical and geometrical elements of the VCBS HD are estimated, and the parallax of the system is modified. Where we can see a good consistency of the physical parameters of the visually close binary systems hip70973 and hip72479 values of the absolute flux and the inclination of the spectrum.
Comparison between the observational and synthetic magnitudes, colors and magnitude differences of the system. This consistency gives a good indication about the reliability of the estimated elements of the individual components of the system, which are listed in Table VI. The estimated masses and radii can only be explained by assuming that the system is a subgiant binary system. The discrepancy between the dynamical and spectral mass estimations is possibly due to their assumption that both components are main-sequence stars, where they used Table VI of , and that the spectral mass represents the minimum mass of the system.
That leads us to suggest that both components are evolved subgiant stars with age around 3. Based on the similarity of both components, fragmen- 3. Where  concludes that fragmentation of a rotating disk around an incipient central protostar is possible, as long as there is continuing infall. A modified orbit and geometrical elements of the system were calculated and compared with earlier ones. Based on the estimated elements, especially radii and masses, we suggest that the two components are F8.
The estimated physical and geometrical elements of the two components coincide within the error values with those given by the Tables of  for subgiants. Finally, fragmentation is proposed as the most likely process for the formation and evolution of both systems. Moreover, the system can be used to test the stellar evolution theory and constraints on the physical description of the stellar interiors.
The authors express the sincere thanks to Dr. Smithsonian Astrophysical Observatory, Remember me Forgot password?
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