Uzay Bilimleri ve Teknolojileri Bölümü Koleksiyonu

Bu koleksiyon için kalıcı URI

https://hdl.handle.net/20.500.12428/2252

Listeleniyor 1 - 20 / 24

Analysis of Apsidal Motion and Light Curves of Three Eccentric Eclipsing Binaries: V398 Lac, V2544 Cyg and V785 Cas
(Iop Publishing Ltd, 2025) Bulut, İbrahim
In this study, the apsidal motion analyses of the eclipsing binary systems V398 Lac, V2544 Cyg, and V785 Cas are presented. The (O − C) diagrams of the selected systems were constructed using all available and reliable times of minimum light compiled from the literature. As a result, the apsidal motion periods were determined to be 353 ± 50 yr, 43.3 ± 5.1 yr and 83.4 ± 8.5 yr, respectively. Furthermore, the TESS light curves of the three systems were analyzed to derive their photometric and absolute parameters. The component masses were determined as follows: for V398 Lac, M1 = 3.83 ± 0.35 M⊙ and M2 = 3.27 ± 0.35 M⊙; for V2544 Cyg, M1 = 1.75 ± 0.38 M⊙ and M2 = 1.40 ± 0.38 M⊙; for V785 Cas, M1 = 5.64 ± 0.41 M⊙ and M2 = 5.18 ± 0.41 M⊙. The parameters related to apsidal motion, as well as the observational and theoretical internal structure constants (k2,obs and k2,teo), were calculated for studied binaries. The relativistic contribution to the observed apsidal motion rate was found to be relatively small, constituting less than approximately 5% of the total rate in each system. The theoretical internal structure constants were derived from the evolutionary models, assuming a standard chemical composition of (X, Z) = (0.70, 0.01).
Dynamic Evolution of the Eclipsing Overcontact Binary Star System BI CVn
(Iop Publishing Ltd, 2025) Bulut, İbrahim; Güneş, M.; Nehir, C.
We present a comprehensive analysis of BI CVn, an eclipsing overcontact binary system. New BVR photometric observations, combined with available spectroscopic data, were analyzed simultaneously using the Wilson-Devinney method to derive the orbital and physical parameters of the system. The resulting stellar parameters are M-1 = 0.58 +/- 0.01M(circle dot), M-2 = 1.42 +/- 0.02M(circle dot), R-1 = 0.88 +/- 0.01R(circle dot), R-2 = 1.31 +/- 0.01R(circle dot), with an orbital separation of a = 2.80 +/- 0.01R(circle dot). Based on all available CCD times of minimum light, including both ground-based and TESS observations, the (O - C) diagram of BI CVn was analyzed. The orbital period exhibits a long-term decrease at a rate of -2.3239 (+/- 0.0001) x 10(-8) day yr(-1), likely due to mass transfer from the more massive to the less massive component. Superimposed on this trend is a cyclic variation with a period of 56.84 +/- 0.08 yr, indicative of a light-travel time effect caused by a third body, whose estimated mass is 0.63 +/- 0.02M(circle dot). Using these derived parameters, we modeled the binary's evolution through non-conservative processes with the Binary Star Evolution code. The evolutionary tracks of the components were examined in multiple parameter planes, leading to an estimated merger timescale of approximately 2.70 Gyr.
Spectroscopic and photometric investigation of some potentially chemically peculiar δ Scuti stars
(Oxford Univ Press, 2025) Kahraman Aliçavuş, Filiz; Aliçavuş, Fahri; Özkardeş, Burcu; Çelik, Eda
Investigating chemically peculiar pulsating stars is crucial for understanding the pulsation driving mechanism in detail. To reveal the true peculiarity properties of stars, detailed spectroscopic analysis is essential. Therefore, in this study, we focused on delta Scuti stars previously identified as chemically peculiar but which needed comprehensive updated spectroscopic analysis to uncover their chemical abundance structure. We selected 10 targets which have publicly available high-resolution spectroscopic and photometric data. Performing spectral analyses, we determined the spectral classification, atmospheric parameters, and detailed chemical abundance distributions of the selected stars. The pulsation properties were also analyzed using TESS data, and pulsation modes for the highest amplitude pulsation frequencies were derived. We estimated the masses and ages of the targets using the evolutionary tracks and isochrones. As a result of our study, we show that only three targets exhibit chemical peculiarity: AU Scl and FG Eri as metallic A (Am) stars, and HZ Vel as a lambda Bootis. However, others were found to be chemically normal stars. This study show us the importance of chemical abundance analysis in the classification of chemical peculiar stars.
New spectroscopic observations of the semidetached binary V375 Cas
(Slovak Academy Sciences Astronomical Inst, 2025) Özkardeş, Burcu; Bakış, H.
We present the low resolution (R similar to 5099) spectroscopy of the eclipsing binary V375 Cas (TIC 326630342) in this study. The low resolution spectroscopic observations of the system were made at the TUBITAK National Observatory using a TFOSC spectrograph in 2020 and 2021. For measuring the radial velocities of both components of the eclipsing binary Gaussian fitting method was used. According to Keplerian orbital solution the spectroscopic mass ratio of the close binary was determined as 0.626 +/- 0.098. The best fitting orbital elements are a1sin i = 0.0243 +/- 0.0018 au, a2sin i= 0.0351 +/- 0.0018 au, M1sin3 i = 7.06 +/- 0.87 Mo and M2sin3 i = 4.42 +/- 0.75 Mo.
Detection of oscillation-like patterns in eclipsing binary light curves using neural network-based object detection algorithms
(Edp Sciences S A, 2025) Ulaş, Burak; Szklenar, T.; Szabo, R.
Aims. The primary aim of this research is to evaluate several convolutional neural network-based object detection algorithms for identifying oscillation-like patterns in light curves of eclipsing binaries. This involved creating a robust detection framework that can effectively process both synthetic light curves and real observational data. Methods. The study employs several state-of-the-art object detection algorithms, including Single Shot MultiBox Detector, Faster Region-based Convolutional Neural Network, You Only Look Once, and EfficientDet, as well as a custom non-pretrained model implemented from scratch. Synthetic light curve images and images derived from observational TESS light curves of known eclipsing binaries with a pulsating component were constructed with corresponding annotation files using custom scripts. The models were trained and validated on established datasets, which was followed by testing on unseen Kepler data to assess their generalisation performance. The statistical metrics were also calculated to review the quality of each model. Results. The results indicate that the pre-trained models exhibit high accuracy and reliability in detecting the targeted patterns. The Faster Region-based Convolutional Neural Network and You Only Look Once in particular showed superior performance in terms of object detection evaluation metrics on the validation dataset, including a mean average precision value exceeding 99%. The Single Shot MultiBox Detector, on the other hand, is the fastest, although it shows a slightly lower performance, with a mean average precision of 97%. These findings highlight the potential of these models to significantly contribute to the automated determination of pulsating components in eclipsing binary systems and thus facilitate more efficient and comprehensive astrophysical investigations.
Quark and strange quark matter in f(R) gravity for Bianchi type I and V space-times
(Springer/Plenum Publishers, 2012) Yılmaz, İhsan; Baysal, Hüsnü; Aktaş, Can
Behaviors of quark matter and strange quark matter which exist in the first seconds of the early Universe in f(R) gravity are studied for Bianchi I and V universes. In this respect, we obtain exact solutions of the modified Einstein field equations by using anisotropy feature of Bianchi I and V space-times. In particular, we investigate exact f(R) functions for Bianchi I as the contribution of strange quark and quark matter. Also, we have concluded that quark matter may contribute to the early acceleration of the universe since quark matter behaves like phantom-type dark energy. Furthermore, obtained f(R) solutions represents early eras of the Universe since f(R) solutions for quark matter coincide with f(R) equations for inflation. From this point, we can reach the conclusion that quarks may be source of the early dark energy of the universe or source of little inflation due to their repulsive force.
STUDY OF ECLIPSING BINARY AND MULTIPLE SYSTEMS IN OB ASSOCIATIONS. II. THE CYGNUS OB REGION: V443 Cyg, V456 Cyg, AND V2107 Cyg
(Iop Publishing Ltd, 2014) Bakış, V.; Hensberge, H.; Bilir, S.; Bakış, H.; Yılmaz, F.; Kıran, E.; Demircan, O.
Three presumably young eclipsing binary systems in the direction of the Cygnus OB1, OB3, and OB9 associations are studied. Component spectra are reconstructed and their orbits are determined using light curves and spectra disentangling techniques. V443 Cyg and V456 Cyg have circular orbits while the light curve of V2107 Cyg imposes a slightly eccentric orbit (e = 0.045 +/- 0.03). V443 Cyg harbors F-type stars, not young early-A stars as previously suggested in the literature based solely on photometry. It appears to be situated in the foreground (distance 0.6 +/- 0.2 kpc) of the young stellar populations in Cygnus. V456 Cyg, at a distance of 0.50 +/- 0.03 kpc, consists of a slightly metal-weak A-type star and an early-F star. The age of both systems, on or very near to the main sequence, remains uncertain by an order of magnitude. V2107 Cyg is a more massive system (8.9 +/- 2 and 4.5 +/- 1.2M(circle dot)) at 1.5 +/- 0.5 kpc and, also kinematically, a strong candidate-member of Cyg OB1. The more massive component is slightly evolved and appears to undergo non-radial beta Cep-type pulsations. The Doppler signal of the secondary is barely detectable. A more extensive, asteroseismological study is necessary to fix masses more precisely. Nevertheless, the position of the primary in the H-R diagram confines the age reasonably well to 20 +/- 5 Myr, indicating that for Cyg OB1 has a similar extent of star formation history as that established for Cyg OB2.
Discovery of delta Scuti variables in eclipsing binary systems II. Southern TESS field search
(Oxford Univ Press, 2023) Kahraman Aliçavuş, Filiz; Çoban, C. G.; Çelik, E.; Doğan, D. S.; Ekinci, O.; Aliçavuş, Fahri
The presence of pulsating stars in eclipsing binary systems (EBs) makes these objects significant since they allow us to investigate the stellar interior structure and evolution. Different types of pulsating stars could be found in EBs, such as δ Scuti variables. δ Scuti stars in EBs have been known for decades, and the increasing number of such systems is important for understanding pulsational structure. Hence, in this study, research was carried out on the southern TESS field to discover new δ Scuti stars in EBs. We produced an algorithm to search for detached and semidetached EBs considering three steps: the orbital period (Porb)’s harmonics in the Fourier spectrum, skewness of the light curves, and classification of upsilon program. If two of these steps classify a system as an EB, the algorithm also identifies it as an EB. The TESS pixel files of targets were also analysed to see whether the fluxes were contaminated by other systems. No contamination was found. We researched the existence of pulsation through EBs with a visual inspection. To confirm δ Scuti-type oscillations, the binary variation was removed from the light curve, and residuals were analysed. Consequently, we identified 42 δ Scuti candidates in EBs. The Porb, L, and MV of systems were calculated. Their positions on the H–R diagram and the known orbital-pulsation period relationship were analysed. We also examined our targets to see if any of them showed frequency modulation with the orbital period and discovered one candidate of tidally tilted pulsators.
On the nature of the eccentric eclipsing binary star SY Phe with a pulsating ? Dor component
(Oxford Univ Press, 2024) Erdem, Ahmet; Sürgit, Derya; Engelbrecht, Chris A.; Zasche, Petr; Bakış, Volkan; Marang, Fred
Spectroscopic observations of the eccentric binary system SY Phe were made at the South African Astronomical Observatory in 2019, 2020, and 2021, and its mid-resolution spectra were obtained. The radial velocities of the component stars were measured using the cross-correlation method and Fourier disentangling of the spectra. The spectral type (hence the effective temperature) of the primary star was determined from a model-atmosphere analysis. The radial velocity and Transiting Exoplanet Survey Satellite ( TESS ) light curves of the system were analysed, and its absolute parameters were derived. A strong (5.2 mmag) periodic signal with a frequency typical of gamma Dor stars (1.169 cycles per day) dominates the Fourier spectrum of the light curve between the eclipses. Apsidal motion parameters of SY Phe were calculated by studying eclipse timing variations. The Geneva evolution models indicate an evolutionary age of 2 Gyr and solar metallicity for the primary component; however, although the position of the secondary component in the H-R diagram matches the isochrone of 2Gyr, it appears to have a larger radius and higher effective temperature than expected for its determined mass. Here, the secondary component has too large a radius, which is in accordance with the radius discrepancy problem that has been encountered in other studies, especially in late-type dwarfs, and has not been solved for half a century.
The Catalogue of Stellar Parameters from the Detached Double-Lined Eclipsing Binaries in the Milky Way
(Cambridge Univ Press, 2014) Eker, Z.; Bilir, Selçuk; Soydugan, Faruk; Yaz Gökçe, Esma; Soydugan, Esin; Tüysüz, Mehmet; Şenyüz, Tunç; Demircan, Oya
The most accurate stellar astrophysical parameters were collected from the solutions of the light and the radial velocity curves of 257 detached double-lined eclipsing binaries in the Milky Way. The catalogue contains masses, radii, surface gravities, effective temperatures, luminosities, projected rotational velocities of the component stars, and the orbital parameters. The number of stars with accurate parameters increased 67% in comparison to the most recent similar collection by Torres, Andersen, & Gimenez (2010). Distributions of some basic parameters were investigated. The ranges of effective temperatures, masses, and radii are 2 750 < T-eff (K)< 43 000, 0.18 < M/M-circle dot < 33, and 0.2 < R/R-circle dot < 21.2, respectively. Being mostly located in one kpc in the Solar neighborhood, the present sample covers distances up to 4.6 kpc within the two local Galactic arms, Carina-Sagittarius and Orion Spur. The number of stars with both mass and radius measurements better than 1% uncertainty is 93, better than 3% uncertainty is 311, and better than 5% uncertainty is 388. It is estimated from the Roche lobe filling factors that 455 stars (88.5% of the sample) are spherical within 1% of uncertainty.
First detailed study of two eccentric eclipsing binaries: TYC 5378-1590-1 and TYC 8378-252-1
(Edp Sciences S A, 2023) Zasche, P.; Sürgit, Derya; Erdem, Ahmet; Engelbrecht, C. A.; Marang, F.
Aims. The analysis of combined photometry and spectroscopy of eccentric eclipsing binary systems facilitates the derivation of very precise values for a large ensemble of physical parameters of the component stars and their orbits, thereby providing stringent tests of theories of stellar structure and evolution. In this paper two eccentric eclipsing binary systems, TYC 5378-1590-1 and TYC 8378252-1, are studied in detail for the first time. Methods. Radial velocities were obtained using cross-correlation methods applied to mid-resolution spectra covering almost the entire orbital phase domains of these two systems. TESS photometry was used for the analysis of TYC 5378-1590-1, whereas ASAS-SN photometry was used for the analysis of TYC 8378-252-1. Results. We obtained the first precise derivation of the physical parameters of these systems. Both systems display moderately eccentric orbits (e similar to 0:3 and 0:2) with periods of 3.73235 and 2.87769 days, respectively. The apsidal motion is very slow, with a duration of several centuries for both systems. We present two models for the apsidal motion of TYC 5378-1590-1. The internal structure constant derived from observations for TYC 8378-252-1 is approximately 11% lower than theoretical predictions. We discuss possible reasons for this discrepancy. Our analysis indicates that the components of both systems are on the main sequence. The components of TYC 5378-1590-1 are relatively young stars (age similar to 600 Myr) close to the ZAMS, whereas the components of TYC 8378-252-1 are relatively old stars (age similar to 4 Gyr) close to the TAMS. Our finding that the circularization timescale for TYC 5378-1590-1 is similar to 200 times longer than its evolutionary age is compatible with circularization theory; however, our finding that the evolutionary age of TYC 8378-252-1 is approximately ten times longer than the circulation age, while its orbital eccentricity is quite high (e similar to 0:2), challenges the present theories of circularization.
Absolute Parameters of Detached Binaries in the Southern Sky - I: V349 Ara and V4403 Sgr
(Cambridge Univ Press, 2015) Erdem, Ahmet; Sürgit, Derya; Engelbrecht, C. A.; Van Heerden, H. P.
We present the first analysis of spectroscopic and photometric observations of the two southern eclipsing binary stars, V349 Ara and V4403 Sgr. Radial velocity curves of these two systems obtained at the South African Astronomical Observatory and their V light curves from the All Sky Automated Survey were solved simultaneously using the Wilson-Devinney code. Our photometric models describe these two systems as Algol-like binary stars with detached configurations. The masses and radii were found to be 2.59 +/- 0.07 M, 3.60 +/- 0.07 R and 2.51 +/- 0.06 M, 4.15 +/- 0.07 R for the primary and secondary components of V349 Ara, respectively. Those of V4403 Sgr were derived to be 1.33 +/- 0.02 M, 1.74 +/- 0.02 R and 1.59 +/- 0.03 M, 2.50 +/- 0.03 R for the primary and secondary components, respectively. The distances to V349 Ara and V4403 Sgr were computed to be 677 +/- 36 and 199 +/- 10 pc from the dynamic parallax, respectively, taking into account interstellar extinction. The evolution cases of these two systems are also examined. Both components of these two systems are evolved main-sequence stars, and the dynamic ages were estimated as approximately 0.67 and 2.29 Gyr for V349 Ara and V4403 Sgr, respectively, when compared to Geneva theoretical evolution models.
Apsidal motion and absolute parameters of GV Nor and V881 Sco based on mid-resolution spectroscopy and TESS photometry
(Oxford University Press, 2023) Sürgit, Derya; Zasche, Petr; Hadrava, Petr; Erdem, Ahmet; Engelbrecht, Chris A.; Marang, Fred; Masek, Martin
The veracity of stellar evolution models and theoretical internal structure constants may be subjected to stringent tests by using physical parameters obtained from spectroscopic and photometric observations of eclipsing binary systems that exhibit apsidal motion. Two eclipsing binary stars from the southern hemisphere with no prior published spectroscopic analyses were selected for this study: GV Nor and V881 Sco. Spectroscopic observations of these two eccentric binary systems were made at the South African Astronomical Observatory (SAAO) in 2018 and 2019, and their mid-resolution spectra were obtained. The radial velocities were measured using the cross-correlation method as well as by disentangling the spectra. The rotational broadening of the disentangled spectra of the components was also determined. The absolute parameters of these two systems were obtained by analyzing the SAAO-based spectroscopic data in conjunction with photometric data from Transiting Exoplanet Survey Satellite. Apsidal motion parameters for these two eccentric binary systems were calculated by analysing eclipse timing variations. Granada and Padova evolution models indicated ages of 340 ± 35 Myr for GV Nor and 760 ± 15 Myr for V881 Sco, in agreement with the observational results. The theoretical internal structure constants estimated from the Granada models were compatible with the observational values within the error limits. However, for both systems, it was found that their circularization and synchronization timescales were shorter than their respective evolutionary ages. Therefore, the fact that the components rotate faster than their synchronized values and still have rather large eccentric orbits (e ∼ 0.11) challenges present theories of circularization and spin–orbit synchronization.
Non-existence of a massive scalar field for the Marder universe in Lyra and Riemannian geometries
(Elsevier, 2012) Aygün, Sezgin; Aktaş, Can; Yılmaz, İhsan
In this paper, we have studied a massive scalar field for a Marder type universe in the context of Lyra and Riemannian geometries. From the exact solutions obtained we show that the massive scalar field does not survive in Lyra and Riemannian geometries for an anisotropic Marder type universe. Therefore we have solved the massless scalar field problem in Lyra and Riemann geometries for two cases. Also we have obtained vacuum solutions for homogeneous and anisotropic Marder space time in Lyra geometry and the solutions obtained are compared by considering Lyra and Riemann geometries. Finally, some physical and kinematical properties are discussed by using graphics. (C) 2011 Elsevier B.V. All rights reserved.
Behaviors of dark energy and mesonic scalar field for anisotropic universe in f (R) gravity
(Elsevier, 2012) Aktaş, Can; Aygün, Sezgin; Yılmaz, İhsan
In this Letter, we study behaviors of dark energy in the form of perfect fluid and mesonic scalar field for Marder space-time which is anisotropic and homogeneous in f (R) gravity. Exact solutions of the modified Einstein field equations in f (R) gravity are obtained by using anisotropic features, of Marder space-time. We do not make any assumptions about f (R) function while we are solving f (R I equations. We have investigated dark energy behaviors in f (R) gravity. We have concluded that dark energy in our model behaves like phantom type. Also we have concluded that mesonic scalar field transforms to another matters into time. In our solutions, obtained f (R) functions existed by dark energy and mesonic scalar field are same like general one accepted in the literature. Furthermore, physical and kinematical quantities are examined for two matters, separately. Finally obtained solutions are discussed. (C) 2011 Elsevier B.V. All rights reserved.
Absolute Parameters of Three F Type Southern Eclipsing Binary Stars: VW Ret, FW Vel, and CW Eri
(Copernicus Foundation for Polish Astronomy, 2024) Zasche, P.; Sürgit, Derya; Erdem, A.; Marang, F.; Engelbrecht, C.A.
This study presents the first detailed analysis of three southern eclipsing binaries. Both – light curves and radial velocity curves – were studied together with their period changes, revealing basic physical and orbital properties of these systems. All three stars, VW Ret, FW Vel, and CW Eri are detached binaries with a few days orbital period. Thanks to our detailed analysis we revealed that all the component stars are slightly heavier than the Sun, laying in the mass range between 1.3 M and 1.6 M . The systems VW Ret, and FW Vel seem to have more dominant secondary components, both in the masses, as well as in luminosities. The system VW Ret is a triple star showing large eclipse times variations with the periodicity of 4 yr. For FW Vel a similar weak variation was also found, but with much lower amplitude of about 56 s only, needed to be independently confirmed. CW Eri shows slightly eccentric orbit (e = 0.015), but only very slow apsidal motion. Moreover, its ages for both component do not agree with each other very well. Hence, it provides a challenge for future more detailed modeling of this interesting system.
Discovery of ? Sct components in eclipsing binary systems IQ CMa, AW men and W Vol
(Oxford University Press, 2023) Ulaş, Burak; Ulusoy, Ceren
We present the first evidence on the δ Sct type pulsations of the primary components of three eclipsing binaries IQ CMa, AW Men, and W Vol in the Transiting Exoplanet Survey Satellite (TESS) field. A comprehensive investigation of the binary properties is conducted. The light curves of the systems are analysed and the frequency analyses are performed to residual data. The systems are compared to the binaries of the same morphological types, and the primaries are examined in contrast to the δ Sct type pulsators. The results show that the systems are oscillating eclipsing Algol-type systems.
Six Newly Discovered Eclipsing Binary Systems in the TESS field
(Institute of Physics, 2023) Ulaş, Burak; Ayan, Vildan
We present the first detailed investigation of six eclipsing binary systems in the TESS field. The TESS light curves of the targets are analyzed by determining the initial effective temperatures via SED fits. The absolute parameters are derived and the systems are compared to well-known binaries of the same type. Results show that CD-58791, CD-621257 and TYC 9356-355-1 are detached binary systems. CD-54942 and UCAC4 136-007295 are contact binaries while TYC 8508-1413-1 is a semidetached system.
V355 And: a neglected detached binary in a multiple star system
(Astronomical Institute, Slovak Academy of Sciences, 2021) Özkardeş, Burcu
The analysis of light curves (from TESS, ASAS-SN and KWS databases) of the eclipsing binary V355 And is presented for the first time. The O-C diagram was constructed using all available times of minimum light together with the ones determined in this study, and the revised ephemeris was obtained. The final photometric model describes V355 And as an Algollike type binary star with a detached configuration. Absolute parameters of the components of the system were found to be: masses, M1=1.56 ± 0.01 M⊙ and M2=1.38 ± 0.01 M⊙, radii, R1=1.70 ± 0.03 R⊙ and R2=1.38 ± 0.03 R⊙, and effective temperatures, T1=6650 ± 200 K and T2=6235 ± 201 K. Considering interstellar extinction the distance to V355 And was computed as 117 ± 7 pc. The evolutionary state of V355 And is also discussed using the Geneva stellar models.
Photometric and period analysis of the eclipsing binary system V2783 Ori
(Astronomical Institute, Slovak Academy of Sciences, 2021) Bulut, İbrahim; Bulut, Ahmet
In this study we performed the first detailed photometric and period analysis of the recently discovered eclipsing binary star V2783 Ori. The analysis of the light curve has shown that the system is in a detached configuration, with the orbital eccentricity e = 0.274 ± 0.008. The photometric mass ratio of V2783 Ori determined from the light curve analysis is q= 0.734 ± 0.015. The absolute parameters of the system were obtained as a result of the light curve solution. Absolute parameters were found as follows: masses M1 = 1.80 ± 0.01 M⊙, M2 = 1.32 ± 0.01 M⊙, radii R1= 2.19 ± 0.10 R⊙, R2= 1.91 ± 0.10 R⊙, temperatures T1= 8325 ± 100 K and T2= 8300 ± 100 K. A comparison of these parameters with theoretical stellar models show that the secondary component is located inside the main-sequence band and still close to ZAMS, while the primary component is located in the middle of ZAMS-TAMS limits. The distance of the system determined from the absolute parameters, d= 1064 ± 150 pc, takes into account the interstellar reddening. The (O-C) diagram was discussed considering all reliable minima times found in the literature and new values for the parameters of the apsidal motion and light-time effect were found. The apsidal motion rate of V2783 Ori is co = 0.0063 ± 0.0017 deg cycle-, and it corresponds to an apsidal motion period of U= 656 ± 103 yr. The third body orbital period is 10 ± 2 yr, its minimal mass is 0.82 ± 0.11 M⊙.

Güncel Gönderiler