Velocity curve analysis of the spectroscopic binary stars RZ Cas, CC Cas, HS Her, HD 93917, V921 Her and Y Cygni by the artificial neural networks

Karami, K.; Ghaderi, K.; Mohebi, R.; Soltanzadeh, M. M.

doi:10.1002/asna.200911240

Cited by 4 publications

(6 citation statements)

References 22 publications

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“…They redetermined the mass ratio of the binary system to be = 0.244 and set the effective temperature of the primary star to be 1 = 7700 K. Their results concluded that V921 Her was a shallow contact binary system. However, Karami and Mohebi [5] and Karami et al [6] also obtained the mass ratio of V921 Her, both of which were consistent with those determined by Rucinski et al [3].…”

Section: Introductionsupporting

confidence: 87%

The Photometric Investigation of V921 Her Using the Lunar-Based Ultraviolet Telescope of Chang’e-3 Mission

Xiao

Qian

Zhang

et al. 2016

Advances in Astronomy

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The light curve of V921 Her in ultraviolet band observed by the Lunar-based Ultraviolet Telescope (LUT) is analyzed by the WilsonDevinney code. Our solutions conclude that V921 Her is an early type marginal contact binary system with an additional closein component. The binary system is under poor thermal contact with a temperature difference of nearly 700 K between the two components. The close-in component contributes about 19% of the total luminosity in the triple system. Combining the radial velocity study together with our photometric solutions, the mass of the primary star and secondary one is calculated to be 1 = 1.784 (±0.055) ⊙ , 2 = 0.403 (±0.012) ⊙ . The evolutionary scenario of V921 Her is discussed. All times of light minimum of V921 Her available in the bibliography are taken into account and the − curve is analyzed for the first time. The most probable fitting results are discussed in the paper, which also confirm the existence of a third component ( 3 = 10.2 year) around the binary system. The period of V921 Her is also undergoing a continuously rapid increase at a rate of / = +2.79 × 10 −7 day ⋅ year −1 , which may be due to mass transfer from the less massive component to the more massive one.

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Section: Introductionsupporting

confidence: 87%

The Photometric Investigation of V921 Her Using the Lunar-Based Ultraviolet Telescope of Chang’e-3 Mission

Xiao

Qian

Zhang

et al. 2016

Advances in Astronomy

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“…The star has also been observed by Hipparcos and new UBV observations were secured during the 1999 observing campaign in Hvar, Korea, and with the Four College APT in Arizona. Hvar observations continued in 2006and 2009. In 2006, two eclipses in BVR were observed by PS.…”

Section: Photometrymentioning

confidence: 81%

“…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.…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Harmanec

Holmgren²,

Wolf

et al. 2014

A&A

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Context. Rapid advancements in light-curve and radial-velocity curve modelling, as well as improvements in the accuracy of observations, allow more stringent tests of the theory of stellar evolution. Binaries with rapid apsidal advance are particularly useful in this respect since the internal structure of the stars can also be tested. Aims. Thanks to its long and rich observational history and rapid apsidal motion, the massive eclipsing binary Y Cyg represents one of the cornerstones of critical tests of stellar evolutionary theory for massive stars. Nevertheless, the determination of the basic physical properties is less accurate than it could be given the existing number of spectral and photometric observations. Our goal is to analyse all these data simultaneously with the new dedicated series of our own spectral and photometric observations from observatories widely separated in longitude. Methods. We obtained new series of UBV observations at three observatories separated in local time to obtain complete light curves of Y Cyg for its orbital period close to 3 days. This new photometry was reduced and carefully transformed to the standard UBV system using the HEC22 program. We also obtained new series of red spectra secured at two observatories and re-analysed earlier obtained blue electronic spectra. Reduction of the new spectra was carried out in the IRAF and SPEFO programs. Orbital elements were derived independently with the FOTEL and PHOEBE programs and via disentangling with the program KOREL. The final combined solution was obtained with the program PHOEBE. Results. Our analyses provide the most accurate value of the apsidal period of (47.805 ± 0.030) yr published so far and the following physical elements: M 1 = 17.72 ± 0.35 M , M 2 = 17.73 ± 0.30 M , R 1 = 5.785 ± 0.091 R , and R 2 = 5.816 ± 0.063 R . The disentangling thus resulted in the masses, which are somewhat higher than all previous determinations and virtually the same for both stars, while the light curve implies a slighly higher radius and luminosity for star 2. The above empirical values imply the logarithm of the internal structure constant log k 2 = −1.937. A comparison with Claret's stellar interior models implies an age close to 2 × 10 6 yr for both stars. Conclusions. The claimed accuracy of modern element determination of 1-2 per cent still seems a bit too optimistic and obtaining new high-dispersion and high-resolution spectra is desirable.

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Eccentric orbits and apsidal motion in the eclipsing binaries EK Cep and HS Her

Latković

Gazeas

Markov

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We present the first modern analysis of two young, eclipsing binaries, EK Cep and HS Her, based on new, ground-based, CCD multicolour light curves as well as the TESS observations, radial velocity curves, and eclipse timing measurements. The orbital and stellar parameters of the stars are determined by Roche modelling, and their evolutionary status is examined using a grid of isochrones and evolutionary tracks. We find that HS Her is 25-32 Myr old and its components are on the zero-age main sequence; at the age of 16-20 Myr, the primary of EK Cep is also on the ZAMS, but its secondary is a pre-main-sequence star. Both binaries have slightly eccentric orbits and display apsidal motion. Based on updated eclipse timings and spectroscopic evidence, we rule out the presence of a previously hypothesized tertiary component in HS Her.

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Velocity curve analysis of the spectroscopic binary stars RZ Cas, CC Cas, HS Her, HD 93917, V921 Her and Y Cygni by the artificial neural networks

Cited by 4 publications

References 22 publications

The Photometric Investigation of V921 Her Using the Lunar-Based Ultraviolet Telescope of Chang’e-3 Mission

The Photometric Investigation of V921 Her Using the Lunar-Based Ultraviolet Telescope of Chang’e-3 Mission

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

Eccentric orbits and apsidal motion in the eclipsing binaries EK Cep and HS Her

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