Velocity curve analysis of the spectroscopic binary stars by the non-linear least squares

Abstract

1 etermining the orbital elements of the binary stars help us to obtain the necessary information such as the mass and the radius of stars which play the important roles during the evolutions of the stellar structures. Analyzing both the light and the radial velocity curves deducing from the photometric and the spectroscopic observations, respectively, yields to derive the orbital parameters. One of the usual methods to analyze the velocity curve is the method of Lehmann-Filhés (Smart 1990). Here we introduce a new method to derive these parameters by the nonlinear regression of the radial velocity-acceleration curves. We test our method for the three double-line spectroscopic binary systems RZ Cas, CC Cas and V1130 Tau which have the following properties.The Algol system RZ Cas is the semi-detached eclipsing binary stars with a period P = 1.195 days. There is a mass transfer between the two components. Some evidences existed for periodicity in the period changes due to apsidal motion. RZ Cas is also a radio source and an X-ray source. See Riazi et al. (1994) and Maxted et al. (1994) and references therein. CC Cas is the massive O-type binary system with a period P = 3.366 days. This system is a detached binary with the two components within the main sequence band. It is an actively interacting system. The system shows a mass loss rate 3 × 10 −7 m ⊙ yr −1 due to the stellar winds. Such mass loss from the system yields to a change in the orbital period by the rate of less than 3 × 10 −6 days per century ). V1130 Tau is a very

New Radial Velocity Studies and Curve Analysis of Spectroscopic Binary Systems CS22964-161, LV Her, RW Lac and HD 34700

“…The combined spectroscopic elements including (15) and (16) in Karami and Teimoorinia [4]. The results obtained for the four systems are tabulated in Tables 2, 4, 6 and 8 show that our results are in good agreement with the those obtained by Thompson et al [10] for CS22964-161, Torres et al [11] for LV Her, Sandberg Lacy et al [12] for RW Lac, Torres [13] for HD 34700, respectively.…”

“…Some other methods were also introduced by Sterne [2] and Petrie [3]. The different methods of the V R curve analysis have been reviewed in ample detail by Karami & Teimoorinia [4]. Karami & Teimoorinia [4] also proposed a new non-linear least squares velocity curve analysis technique for spectroscopic binary stars.…”

Revised physical elements of the astrophysically important O9.5+O9.5V eclipsing binary system Y Cygni

“…Comparing the disentangled and synthetic spectra, they obtained a new estimate of the T eff and log g for both components. New orbital elements of Y Cyg were derived from the published radial velocities (RVs) of by Karami & Teimoorinia (2007), who used a least-squares technique, and by Karami et al (2009), who used the artificial neural network method and who arrived at virtually identical masses for both stars.…”

“…We circumvent this requirement by combining our efforts from three stations, suitably separated in local time. In 1999, we obtained calibrated UBV photometry of the binary from North America, Redman (1930); C) Vitrichenko (1971); D) Stickland et al (1992); E) ; F) Burkholder et al (1997); G) ; H) Karami & Teimoorinia (2007); I) Karami et al (2009). An asterisk in Col. 5 denotes that the role of the components is inverted with respect to our convention in the original study.…”

Application of a new non-linear least squares velocity curve analysis technique for spectroscopic binary stars

“…Smart, 1990). In the present paper we use the method introduced by Karami & Mohebi (2007a) (=KM2007a) and Karami & Teimoorinia (2007) (=KT2007), to obtain orbital parameters of the nine double-lined spectroscopic binary systems: NSV 223, AB And, V2082 Cyg, HS Her, V918 Her, BV Dra, BW Dra, V2357 Oph, and YZ Cas. Our aim is to show the validity of our new method to a wide range of different types of binary.…”