Physical and geometrical parameters of CVBS X: the spectroscopic binary Gliese 762.1

We present the physical and geometrical parameters of the individual components of the close visual double-lined spectroscopic binary system Gliese 762.1, which were estimated using Al-Wardat's complex method for analyzing close visual binary systems. The estimated parameters of the individual components of the system are as follows: radius RA= 0.845±0.09R⊙, RB= 0.795±0.10R⊙, effective temperature TA eff= 5300luminosity±50 K, TB eff= 5150 L±50 K, surface gravity log gA= 4.52±0.10, log gB=4.54±0.15 and A= 0.51 with a semi-major axis of 0.0865±0.08L⊙, LB= 0.40±0.07L⊙. New orbital elements are presented±0.010 arcsec using the Hippracos parallax π = 58.96 ndividual masses of the system are determined as M = 1.±0.65 mas, and an accurate total mass and i72±0.60 M⊙,MA= 0.89±0.08 M⊙and MB= 0.83 K0 V and±0.07 M⊙. Finally, the spectral types and luminosity classes of both components are assigned as K1.5V for the primary and secondary components respectively,and their positions on the H-R diagram and evolutionary tracks are given.     

Physical and geometrical parameters of VCBS XIII: HIP 105947

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.     

Physical parameters of the binary star CM draconis components

Spectra of the eclipsing binary star CM Dra consisting of two M dwarfs are discussed in detail. High-resolution echelle spectra (R = 47000) obtained using the 4.2 m William Hershel telescope are used. The temperatures and metallicities of both components in the binary system are determined using the stellar spectra simulation: T = 3100 ± 100 K, logg = 5.0 ± 0.2, [M/H] = ?0.5 ± 0.2 dex. The estimated values are in good agreement with the results obtained by other researchers.     

Physical parameters of the O6.5V+B1V eclipsing binary system LS 1135

The 'All Sky Automated Survey' (ASAS) photometric observations of LS 1135, an O-type single-lined binary (SB1) system with an orbital period of 2.7 d, show that the system is also eclipsing performing a numerical model of this binary based on the Wilson–Devinney method. We obtained an orbital inclination     . With this value of the inclination, we deduced masses   M ₁∼ 30 ± 1 M_⊙  and   M ₂∼ 9 ± 1 M_⊙  , and radii   R ₁∼ 12 ± 1 R_⊙  and   R ₂∼ 5 ± 1 R_⊙  for primary and secondary components, respectively. Both the components are well inside their respective Roche lobes. Fixing the T _eff of the primary to the value corresponding to its spectral type (O6.5V), the T _eff obtained for the secondary component corresponds approximately to a spectral type of B1V. The mass ratio   M ₂/ M ₁∼ 0.3  is among the lowest known values for spectroscopic binaries with O-type components.     

Physical and geometrical parameters of CVBS XIV:the two nearby systems HIP 19206 and HIP 84425

Data release 2(DR2) from the Gaia mission was of great help in precise determination of fundamental parameters of Close Visual Binary and Multiple Systems(CVBMSs), especially masses of their components, which are crucial parameters in understanding formation and evolution of stars and galaxies. This article presents the complete set of fundamental parameters for two nearby close visual binary systems(CVBSs), which are HIP 19206 and HIP 84425. We utilised a combination of two methods; the first one is Tokovinin's dynamical method to solve the orbit of the system and to estimate orbital elements and the dynamical mass sum, and the second one is Al-Wardat's method for analysing CVBMSs to estimate the physical parameters of the individual components. The latest method employs grids of Kurucz lineblanketed plane parallel model atmospheres to build synthetic Spectral Energy Distributions(SEDs) of the individual components. Trigonometric parallax measurements given by Gaia DR2 and Hipparcos catalogues are used to analyse the two systems. The difference in these measurements yielded slight discrepancies in the fundamental parameters of the individual components, especially masses. So, a new dynamical parallax is suggested in this work based on the most convenient mass sum as given by each of the two methods. The new dynamical parallax for the system HIP 19205 of 22.97±0.95 mas coincides well with the trigonometric one reported recently(in December 2020) by Gaia EDR3 of 22.3689 ± 0.4056 mas. The positions of the components of the two systems on the evolutionary tracks and isochrones are plotted, which suggest that all components are solar-type main sequence stars. Their most probable formation and evolution scenarios are also discussed.     

Physical and geometrical parameters of CVBS. XII. FIN 350 (HIP 64838)

A complete astrophysical and dynamical study of the close visual binary system (CVBS) Finsen 350 (A7V + F0V), is presented. Beginning with the entire observational spectral energy distribution (SED) and the magnitude difference between the subcomponents, Al-Wardat’s complex method for analyzing CVBS was applied as a reverse method of building the individual and entire synthetic SEDs of the system. This was combined with Docobo’s analytic method to calculate the new orbits. Although possible short (approximately 9 years) and long period (of about 18 years) orbits could be considered taking into account the similar results of the stellar masses obtained for each of them (3.07 and 3.41 M _⊙, respectively), we confirmed that the short solution is correct. In addition, other physical, geometrical and dynamical parameters of this system such as the effective temperatures, surface gravity accelerations, absolute magnitudes, radii, the dynamical parallax, etc., are reported. The Main Sequence phase of both components with age around 0.79 Gyr is approved.     

Physical parameters of the massive multiple system eta Orionis

Summary The bright massive object η Orionis is at the same time a totally eclipsing system, a spectroscopic triple system, a speckle triple system and a visual binary. These circumstances offer an exceptional opportunity for determining the physical parameters of massive stars. Our observations show that the published elements are wrong. We present a new determination of several parameters of the multiple system and propose new visual observations. Based on observations collected with the Swiss Telescope at the European Southern Observatory, La Silla, Chile.     

Modified physical and geometric parameters of the eclipsing X-ray binary system Centaurus X-3

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.     

Orbital parameters and variability of the emission spectrum for the massive binary system 103 Tau

Based on high-resolution spectra taken near the He I 6678 Å line for the massive binary system 103 Tau, we have detected a weak absorption component belonging to the binary’s secondary component. We have measured the radial velocities of both components, improved the previously known orbital parameters, and determined the new ones. The binary has an orbital period P _orb = 58.305^d, an orbital eccentricity e = 0.277, a radial velocity semi-amplitude of the bright component K _A = 44.8 km s^?1, and a component mass ratio M _A /M _B = 1.77. The absence of photometric variability and the estimates of physical parameters for the primary component suggest that the binary most likely has a considerable inclination of the orbital plane to the observer, i ≈ 50°?60°. In this case, the secondary component is probably a normal dwarf of spectral type B5–B8. Based on the spectra taken near the H _α line, we have studied the variability of the emission profile. It is shown to be formed in the Roche lobe of the secondary component, but no traces of active mass exchange in the binary have been detected.     

The spectroscopic and interferometric orbit of Gliese 150.2

We determined the spectroscopic-interferometric orbit of the binary red dwarf Gliese 150.2 with a period of 13.84 yr and a semimajor axis of 0.257 arcsec. Based on the orbital elements and on accurate measurements of the magnitude difference at several wavelengths, we estimated the spectral types and masses of the components (K0 V and M0 V, 0.79 and 0.55M _⊙) and the dynamical parallax of the binary (40.4 mas).     

Investigation of the parameters of the massive binary X-ray system IGR J17544-2619

The paper presents the results of spectroscopic research of the high-mass X-ray binary IGRJ17544-2619 optical component that were carried out with the RTT-150. The analysis of a long series of spectroscopic observations of the optical star of IGRJ17544-2619 system in 2007–2011 was carried out. Orbital parameters of the system were obtained: γ-velocity of 47 km/s, semiamplitude of radial velocity curve K = 30.5 km/s, eccentricity e = 0.44, longitude of the periastron ω = 142°, and an orbital period of the system of 12.17 days. The lower limit of the compact object mass was found to be equal to M = 2.82M _⊙.     

Determination of the orbital parameters of binary pulsars

We present a simple, novel method for determining the orbital parameters of binary pulsars. This method works with any sort of orbital sampling, no matter how sparse, provided that information on the period derivatives is available with each measurement of the rotational period of the pulsar, and it is applicable to binary systems with nearly circular orbits. We use the technique to estimate precisely the hitherto unknown orbital parameters of two binary millisecond pulsars in the globular cluster 47 Tucanae, 47 Tuc S and T. The method can also be used more generally to make first-order estimates of the orbital parameters of binary systems using a minimal number of data.     

Determination of the orbital parameters of binary pulsars

We present a simple method for determination of the orbital parameters of binary pulsars, using data on the pulsar period at multiple observing epochs. This method uses the circular nature of the velocity space orbit of Keplerian motion and produces preliminary values based on two one-dimensional searches. Preliminary orbital parameter values are then refined using a computationally efficient linear least-squares fit. This method works for random and sparse sampling of the binary orbit. We demonstrate the technique on (i) the highly eccentric binary pulsar PSR J0514−4002 (the first known pulsar in the globular cluster NGC 1851) and (ii) 47 Tuc T, a binary pulsar with a nearly circular orbit.     

Absolute parameters of the Algol binary Z Vul

Spectra in the wavelength range 4230–9150 Å and the first light curves of Z Vul in the infrared J, H and K bands are presented. Our infrared JHK light curves and radial velocities, together with published radial velocity and UBV data are analyzed in order to determine a new set of stellar parameters. This allows us to determine new absolute parameters of the stellar components, the interstellar reddening and the distance to the system. We discuss the rotation of the primary star, finding that must be rotating faster than synchronous. From the visual–infrared photometry we find no evidence of IR excess in the system.     

Orbital and physical parameters of the spectroscopic binary HD37737

We report the physical and orbital parameters of the visible component of the spectroscopic binary HD37737 (m _V = 8.03). The observations were performed with the 1.2-m telescope of the Kourovka Astronomical Observatory of the Ural Federal University in 2012 and the 6-m BTA telescope of the SAO RAS in 2007 and 2009. Radial velocities were measured separately from each spectral line of the list by the cross-correlation method with a synthetic spectrum. The latter was calculated using the grids of non-LTE model atmospheres with solar chemical compositions. A significant difference in the epochs of observations (2005–2012) allowed to refine the orbital period of the star (7 _· ^d 84705) and the orbital elements of the binary system. We obtained an estimate of the mass function f(m) = 0.23 ± 0.02M _⊙. The best agreement between the synthetic and observed spectra is achieved at T _eff = 30 000 K and log g = 3.50 according to the observations on both instruments. The obtained parameters correspond to a star of spectral type O9.5 III, with mass estimated at 26 ± 2M _⊙. The minimum mass estimate of the secondary component of the binary is 6.2 ± 0.5M _⊙. We have discovered a fact that the velocities, obtained from different spectral lines, differ, which is typical for giant stars. Engaging additional spectra, obtained in 2005 with the 2.1-m KPNO telescope, we investigated the effect of this fact on the estimate of the speed of the system’s center of mass. The difference in the velocities of various lines is approximately the same in the spectra, obtained at all the three instruments. The obtained ratios suggest that the deeper layers of the atmosphere of the star are moving with a greater velocity than the outer layers. Depending on the line, the estimate of the heliocentric velocity of the binary’s center of mass varies in the range from ?11 to 1 km/s.     

A modified genetic algorithm for precise determination the geometrical orbital elements of binary stars

The paper presents a modified genetic algorithm called adapted genetic algorithm with adjusting population size (AGA-POP) for precise determination the orbital elements of binary stars. The proposed approach is a simple, robust way that can be considered to be a new member in the class of self organizing genetic algorithms. The proposed AGA-POP is applied on the star η Bootis of MK type G0 IV to find a set of optimal orbital elements. This leads to obtain the best fitting of Keplerian and phase curves. The modified method is compared with other different methods such as standard genetic algorithm, adapted genetic algorithm (AGA) and least square methods. Simulation results show the effectiveness of using AGA-POP compared with other different classic genetic algorithms in reducing the computation time. Also, better performances have been achieved when using the proposed technique.     

Physical parameters of the Jovian atmosphere

The following physical parameters have been computed for the Jovian atmosphere between 270 and ?300 km: (1) Pressure, (2) Density, (3) Speed and sound, (4) Number density, (5) Density scale. It has considered that the top of the clouds is at 0 km. For the calculations of these parameters we have used:

1. for the altitudes 270-0 km data from Voyager I and II.
2. for the altitudes ?300–0 km data from Voyager II and spectroscopic observations.