M. A. Al-Wardat

Physical Parameters of the Visually Close Binary Systems Hip70973 and Hip72479

Atmospheric modelling of the components of the visually close binary systems Hip70973 and Hip72479 was used to estimate the individual physical parameters of their components. The model atmospheres were constructed using a grid of Kurucz solar metalicity blanketed models and used to compute a synthetic spectral energy distribution for each component separately, and hence for the combined system. The total observational spectral energy distributions of the systems were used as a reference for comparison with the synthetic ones. We used the feedback modified parameters and iteration method to obtain the best fit between synthetic and observational spectral energy distributions. The physical parameters of the components of the system Hip70973 were derived as Teffa = 5700 ± 75 K, Teffb = 5400 ± 75 K, logga = 4.50 ± 0.05, log gb = 4.50 ± 0.05, Ra = 0.98 ± 0.07 R⊙, Rb = 0.89 ± 0.07 R⊙, and π = 26.25 ± 1.95 mas, with G4 and G9 spectral types, and those of the system Hip72479 as Teffa = 5400 ± 50 K, Teffb = 5180 ± 50 K, logga =4.50 ± 0.05, loggb = 4.60 ± 0.05, Ra = 0.89 ± 0.07 R⊙, Rb = 0.80 ± 0.07 R⊙, and π = 23.59 ± 1.00 mas, with G9 and K1 spectral types.

Complex Analysis of the Stellar Binary HD25811: A Subgiant System

The visually close binary system HD25811 is analysed to estimate its physical and geometrical parameters in addition to its spectral type and luminosity class. The method depends on obtaining the best fit between the entire observational spectral energy distribution (SED) of the system and synthetic SEDs created by atmospheric modelling of the individual components, consistent with the systems modified orbital elements. The parameters of the individual components of the system are derived as: T a eff = 6850 ± 50 K, T b eff = 7000 ± 50 K, log g a = 4.04 ± 0.10, log g b = 4.15 ± 0.10, R a = 1.96 ± 0.20 R ⊙ , R b = 1.69 ± 0.20 R ⊙ , M a v = 1. m 97 ± 0.20, M b v = 2. m 19 ± 0.20, L a = 7.59 ± 0.70 L ⊙ , L b = 6.16 ± 0.70 L ⊙ with dynamical parallax

Speckle interferometric binary system HD375; Is it a sub-giant binary?

\pi (\textrm {mas})=5.095\pm 0.095

Time dependent action in

. The analysis shows that the system consists of a 1.55 M ⊙ F2 subgiant star and a less evolved 1.50 M ⊙ F1 secondary subgiant star with ages around 2 Gy formed by fragmentation. Synthetic magnitudes of both components were calculated under Johnson-Cousins, Stromgren, and Tycho photometrical systems.

\phi^6

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: Teffa = 6100 ± 50 K, Teffb = 5940 ± 50 K, log ga = 4.01 ± 0.10, log gb = 3.98 ± 0.10, Ra = 1.93 ± 0.20R⊙, Rb = 1.83 ± 0.20R⊙, Mva = 3·m26 ± 0.40, Mvb = 3·m51 ± 0.50, La = 4.63 ± 0.80 L⊙, and Lb = 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 Ma = 1.35M⊙ and Mb = 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.

potential

The false vacuum decay in field theory from a coherently oscillating initial state is studied for 6 potential. An oscillating bubble solution is obtained. The instantaneous bubble nucleation rate is calculated.

Parameters of the visually close binary system Hip11253 (HD14874)

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: Teffa = 6030 ± 100 K, Teffb = 4470 ± 130 K, log ga = 4.27 ± 0.13, log gb = 4.04 ± 0.13, Ra = 1.22 ± 0.09R⊙, Rb = 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.

Synthetic photometry of speckle interferometric binaries

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.

Physical and geometrical parameters of the binary system gliese 150.2

The speckle interferometric binary system Gl 150.2 (HIP17491) is analyzed using atmosphere modeling and dynamical analysis simultaneously. A synthetic spectral energy distribution (SED) for each of the two components of the system is built using Kurucz blanketed models. These SEDs are combined together to form the total flux, which is compared with the observed one in an iterative method to get the best fit. The parameters of the individual components which lead to the best fit are: TeffA = 5350 ± 50 K, TeffB = 4400 ± 50 K, log gA = 4.40 ± 0.05, log gB = 4.68 ± 0.05, RA = 0.95 ± 0.06R⊙, RB = 0.58 ± 0.06R⊙, and π = 38.63 ± 0.79 mas, as given by the modified Hipparcos measurement. A modified orbit of the system is introduced and compared with earlier orbits. Hence, the masses of the two components are derived from the coincidence between the atmosphere modeling and dynamical analysis. Based on the estimated physical and geometrical parameters of the system, which are confirmed by synthetic photometry, the spectral types and luminosity classes of the two components are found to be G9.5V and K7V for the primary and secondary stars respectively, with an age of about 8 Gyr. Finally, the positions of both components on the H-R diagram are plotted, and the formation and evolution of the system are discussed.

Physical and geometric parameters of the evolved binary system HD 6009

Atmospheric modeling and dynamical analysis of the components of the speckle interferometric binary system HD 6009 were used to estimate their individual physical and geometric parameters. Model atmospheres were constructed using a grid of Kurucz’s solar metallicity blanketed models and used to compute the individual synthetic spectral energy distribution (SED) for each component separately. These SEDs were combined together to compute the entire SED for the system from the net luminosities of the components A and B located at a distance d from the Earth. We used the modified feedback parameters and the iteration method to get the best fit between the synthetic and observed total SEDs. The physical and geometric parameters of the system’s components were derived as TeffA = 5625 ± 75 K, TeffB = 5575 ± 75 K, log gA = 3.75 ± 0.25, log gB = 3.75 ± 0.25, RA = 2.75 ± 0.30R⊙, RB = 2.65 ± 0.30 R⊙,