Speckle-interferometric Study of Close Visual Binary System HIP 11253(HD 14874)using Gaia(DR2 and EDR3)

We present a comprehensive set of physical and geometrical parameters for each of the components of the close visual binary system HIP 11253(HD 14874).We present an analysis for the binary and multiple stellar systems with the aim to obtain a match between the overall observational spectral energy distribution of the system and the spectral synthesis created from model atmospheres using Al-Wardat's method for analyzing binary and multiple stellar systems.The epoch positions are used to determine the orbital parameters and the total mass.The parameters of both components are derived as:T_(eff)^(a)=6025,T_(eff)^(b)=4710,logg_(a)=4.55,logg_(b)=4.60,R_(a)=1.125 R_(⊙),R_(b)=0.88R_(⊙),L_(a)=1.849 L_(⊙),L_(b)=0.342 L_(⊙).Our analysis shows that the spectral types of the components are F9 and K3.By combining the orbital solution with the parallax measurements of Gaia DR2 and EDR3,we estimate the individual masses using the H-R diagram as M_(a)=1.09 M_(⊙)and M_(b)=0.59 M_(⊙)for using Gaia DR2 parallax and M_(a)=1.10 M_(⊙)and M_(b)=0.61 M_(⊙)for using Gaia EDR3 parallax.Finally,the location of both system's components on the stellar evolutionary tracks is presented.

Modified Masses and Parallaxes of Close Binary Systems: HD 39438

We present the detailed fundamental stellar parameters of the close visual binary system HD 39438 for the first time. We used Al-Wardat's method for analyzing binary and multiple stellar systems. The method implements Kurucz's plane parallel model atmospheres to construct synthetic spectral energy distributions(SEDs) for both components of the system. It then combines the results of the spectroscopic analysis with the photometric analysis and compares them with the observed ones to construct the best synthetic SED for the combined system. The analysis gives the precise fundamental parameters of the individual components of the system. Based on the positions of the components of HD 39438 on the H-R diagram, and evolutionary and isochrone tracks, we found that the system belongs to the main sequence stars with masses of 1.24 and 0.98 solar masses for the components A and B, respectively, and age of 1.995 Gyr for both components. The main result of HD 39438 is new dynamical parallax, which is estimated to be 16.689 ± 0.03 mas.

The stellar system HIP 101227:is it a binary,a triple or a quadruple system?

In this paper,we present the analysis of the stellar system HIP 101227 to determine the actual number of components in the system,and their properties.We use dynamical modeling and complex spectrophotometric(involving atmospheric modeling)techniques with recent data,to determine the physical properties and orbital solution for the system,respectively,with better accuracy than past studies.Based on our analysis,we found that the system is more consistent with being a quadruple rather than a binary or a triple system as suggested by previous studies.The total mass of the system determined from our SED analysis is 3.42±0.20 M,which is distributed almost equally between the four stars.The stars are found to be zero-age main sequence stars;i.e.,at the last stage of pre-main sequence,with age less than 200 Myr and spectral types K0.All four stars have very similar physical characteristics,suggesting that the fragmentation process is the most likely theory for the formation and evolution of the system.

Physical and geometrical parameters of CVBS Ⅺ: Cou 1511(HIP 12552)

Model atmospheres of the close visual binary star Cou 1511 （HIP 12552） are constructed using grids of Kuruz＇s blanketed models to build the individual synthetic spectral energy distributions （SEDs） for both components. These synthetic SEDs are combined together for the entire system and compared with the observational one following A1-Wardat＇s complex method for analyzing close visual binary stars. The entire observational SED of the system is used as a reference for comparison between the synthetic SED and the observed one. The parameters of both components are derived as： Teff = 6180 4- 50 K, Tebfr = 5865 ＋ 70 K, log 9a = 4.35 ± 0.12, log 9b = 4.45± 0.14, Ra = 1.262 ± 0.08 R⊙^eff, Rb = 1.006 ± 0.07 R⊙^ett, La = 2.09 -4- 0.10 L⊙ and Lb = 1.08 ± 0.12 L⊙, with spectral types F8V and G1.5V for components （a, b） respectively and age of 3.0 ± 0.9 Gyr. A modified orbit of the system is built and the masses of the two components are calculated as Ma = 1.17 ±0.11 Me and Mb = 1.06 ± 0.10 Me.

Physical and orbital properties of the stellar system HIP 43766

In this paper,we present the analysis of the stellar binary system HIP 43766 to determine its properties.We rely on dynamical modeling and atmospheric modeling with recent data to determine the orbital solution and the physical properties of the system.There is a consistency between observed and synthetic photometry obtained using atmospheric modeling.The calculated dynamical mass sum of the system ranged between 1.691 and 2.609 solar masses,while it ranges between 2.0 and 2.1 as estimated utilizing atmospheric modeling.This could be due to inaccuracy in estimating the orbit,which could be modified with future observations with more relative positional measurements.The parameters of the system and the position of the components on the evolutionary tracks show that the system consists of F5 and G5 subgiant stars,mostly formed by fragmentation.A dynamical mass sum is predicted for the system.

Does ADS 9346 have a low-mass companion?

Based on the photographic and CCD observations of the relative motion of the A and B components of the binary system ADS 9346 obtained with the 26-inch refractor of Pulkovo Observatory during 1979–2019,we discover an invisible companion associated with star A.Comparison of the ephemerides with the positional and spectroscopic observations allowed us to calculate the preliminary orbit of the photocenter(P=15 yr).The minimal mass of the companion is approximately 0.13 M.The existence of the invisible low-mass companion is implied by the IR-excess based on IRAS data.To confirm this,additional observations of the radial velocity near the periastron need to be carried out.