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1.
This study presents the absolute parameters of the contact binary system V376 And. CCD photometric observations were made at the Çanakkale Onsekiz Mart University Observatory in 2004. The instrumental magnitudes of all observed stars were converted into standard magnitudes. New BV light curves of the system were analysed using the Wilson–Devinney method supplemented with a Monte Carlo type algorithm. Since there are large asymmetries between maxima (i.e., O’Connell effect) in these light curves, two different models (one with a cool spot and one with a hot spot) were applied to the photometric data. The best fit, which was obtained with a large hot spot on the secondary component, gives V376 And as an A sub-type contact binary in poor thermal contact and a small value of the filling factor (f ≈ 0.07). Combining the solutions of our light curves and Rucinski et al. (2001)’s radial velocity curves, the following absolute parameters of the components were determined: M1 = 2.44 ± 0.04 M⊙, M2 = 0.74 ± 0.03 M⊙, R1 = 2.60 ± 0.03 R⊙, R2 = 1.51 ± 0.02 R⊙, L1 = 40 ± 4 L⊙ and L2 = 5 ± 1 L⊙. We also discuss the evolution of the system, which appears to have an age of 1.6 Gyr. The distance to V376 And was calculated as 230 ± 20 pc from this analysis, taking into account interstellar extinction.  相似文献   

2.
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3.
This paper presents new CCD Bessell BVRI light curves and photometric analysis of the Algol-type binary star TX Her. The CCD observations were carried out at Çanakkale Onsekiz Mart University Observatory in 2010. New BVRI light curves from this study and radial velocity curves from Popper (1970) were solved simultaneously using modern light and radial velocity curves synthesis methods. The general results show that TX Her is a well-detached eclipsing binary, however, both component stars fill at least half of their Roche lobes. A significant third light contribution to the total light of the system could not be determined. Using O–C residuals formed by the updated minima times, an orbital period study of the system was performed. It was confirmed that the tilted sinusoidal O–C variation corresponds to an apparent period variation caused by the light travel time effect due to an unseen third body. The following absolute parameters of the components were derived: M1 = 1.62 ± 0.04 M⊙, M2 = 1.45 ± 0.03 M⊙, R1 = 1.69 ± 0.03 R⊙, R2 = 1.43 ± 0.03 R⊙, L1 = 8.21 ± 0.90 L⊙ and L2 = 3.64 ± 0.60 L⊙. The distance to TX Her was calculated as 155 ± 10 pc, taking into account interstellar extinction. The position of the components of TX Her in the HR diagram are also discussed. The components are young stars with an age of ～500 Myr.  相似文献   

4.
This paper presents the absolute parameters of RZ Dra. New CCD observations were made at the Mt. Suhora Observatory in 2007. Two photometric data sets (1990 BV and 2007 BVRI) were analysed using modern light-curve synthesis methods. Large asymmetries in the light curves may be explained in terms of a dark starspot on the primary component, an A6 type star. Due to this magnetic activity, the primary component would appear to belong to the class of Ap-stars and would show small amplitude with δ Scuti-type pulsations. With this in mind, a time-series analysis of the residual light curves was made. However, we found no evidence of pulsation behaviour in RZ Dra. Combining the solutions of our light curves and Rucinski et al. (2000)’s radial velocity curves, the following absolute parameters of the components were determined: M1 = 1.63 ± 0.03 M⊙, M2 = 0.70 ± 0.02 M⊙, R1 = 1.65 ± 0.02R⊙, R2 = 1.15 ± 0.02 R⊙, L1 = 9.72 ± 0.30 L⊙ and L2 = 0.74 ± 0.10 L⊙. The distance to RZ Dra was calculated as 400 ± 25 pc, taking into account interstellar extinction. The orbital period of the system was studied using updated O–C information. It was found that the orbital period varied in its long-period sinusoidal form, superimposed on a downward parabola. The parabolic term shows a secular period decrease at a slow rate of 0.06 ± 0.02 s per century and is explained by the mass loss via magnetized wind of the Ap-star primary. The tilted sinusoidal form of the period variation may be considered as an apparent change and may be interpreted in terms of the light-time effect due to the presence of a third body.  相似文献   

5.
We obtained multi-colour light curves of the overcontact binary system HH Boo and analysed the orbital period variation of the system. Our analysis tentatively indicates either mass transfer from the secondary to the primary or mass loss from the system at a rate of -5.04 × 10−7 M⊙ per year. Through a combined analysis of the published radial velocity curve and light curves, we determined an inclination (i) of 69°.71 ± 0°.16 and a semi-major axis (a) of 2.246 ± 0.064 R⊙ for HH Boo. The masses of the primary and secondary components were found to be 0.92 ± 0.08 M⊙ and 0.58 ± 0.06 M⊙, respectively. The radius determined for the primary was 0.98 ± 0.03 R⊙, while that determined for the secondary was 0.80 ± 0.02 R⊙. We demonstrated that HH Boo is most likely a member of the A-type subclass of W UMa binaries.  相似文献   

6.
We present the results of our investigation of the geometrical and physical parameters of the W UMa‐type binary V404 Peg from analysis of CCD (BVRI) light curves and radial velocity data. The photometric data were obtained during 2010 at Ankara University Observatory (AUO). Light and radial velocity observations were analyzed simultaneously by using the well‐known Wilson‐Devinney (2007 revision) code to obtain absolute and geometrical parameters. Our solution indicates that V404 Peg is an A‐type overcontact binary with a mass ratio of q = 0.243 and an overcontact degree of f = 32.1 %. Combining our light curves with the radial velocity curves from Maciejewski & Ligeza (2004), we determined the absolute parameters of this system as follows: a = 2.672 R⊙, M1 = 1.175 M⊙, M2 = 0.286 M⊙, R1 = 1.346 R⊙, and R2 = 0.710 R⊙. Finally, we discuss the evolutionary condition of the system (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

7.
In this study, we present the first Johnson BV photometry of the eclipsing binary star ET Bootis, which is member of a physically connected visual pair. Analysis of times of light minima enables us to calculate accurate ephemeris of the system via O–C analysis and observed an increase in period which we believe is a result of the light-time effect in the outer visual orbit. Secondly, we determined the total brightness and color of the system in light maxima and minima. Photometric solution of the system indicates that the contribution of the visual pair to the total light is about 40% in Johnson V band. Furthermore, photometric analysis shows that the primary star in the eclipsing binary has F8 spectral type while it confirms the G5 spectral type for the visual pair. Masses of the components in eclipsing binary are M1 = 1.109 ± 0.014 M⊙ and M2 = 1.153 ± 0.011 M⊙. Absolute radii of the components are R1 = 1.444 ± 0.007 R⊙ and R2 = 1.153 ± 0.007 R⊙. Physical properties of the components leads 176 ± 7 pc distance for the system and suggests an age of 6.5 billion years.  相似文献   

8.
We present new B- and V-band photometry of the W UMa-type binary system QX And, which is a member of the open cluster NGC 752. Revised orbital period and new ephemerides were given for the binary system based on the data of times of light minima. The result of a period analysis reveals that the system is undergoing a continuous orbital period increase during the past decades. The rate of period increasing turns out to be about 2.7 × 10?7 d yr?1. With the Wilson–Devinney code, a photometric solution is computed. It yields a contact configuration for the system with a filling factor of 0.361. Combining the results from the photometric solution along with that from the radial-velocity observations, we have determined the absolute parameters for the two components of the system. The masses, radii and luminosity of the primary and secondary stars are calculated as 1.43 ± 0.04 M⊙, 1.45 ± 0.09 R⊙, 2.87 ± 0.40 L⊙ and 0.44 ± 0.02 M⊙, 0.87 ± 0.05 R⊙, 0.99 ± 0.13 L⊙, respectively. The evolutionary status and physical nature of the contact binary system were discussed compared with the theoretical models.  相似文献   

9.
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10.
This paper presents the first analysis of spectroscopic and photometric observations of the neglected southern eclipsing binary star, QY Tel. Spectroscopic observations were carried out at the South African Astronomical Observatory in 2013. New radial velocity curves from this study and V light curves from the All Sky Automated Survey were solved simultaneously using modern light and radial velocity curve synthesis methods. The final model describes QY Tel as a detached binary star where both component stars fill at least half of their Roche limiting lobes. The masses and radii were found to be 1.32 (± 0.06) M⊙, 1.74 (± 0.15) R⊙ and 1.44 (± 0.09) M⊙, 2.70 (± 0.16) R⊙ for the primary and secondary components of the system, respectively. The distance to QY Tel was calculated as 365 (± 40) pc, taking into account interstellar extinction. The evolution case of QY Tel is also examined. Both components of the system are evolved main-sequence stars with an age of approximately 3.2  Gy, when compared to Geneva theoretical evolution models.  相似文献   

11.
We present the results of the study of the contact binary system BO CVn. We have obtained physical parameters of the components based on combined analysis of new, multi-color light curves and spectroscopic mass ratio. This is the first time the latter has been determined for this object. We derived the contact configuration for the system with a very high filling factor of about 88%. We were able to reproduce the observed light curve, namely the flat bottom of the secondary minimum, only if a third light has been added into the list of free parameters. The resulting third light contribution is significant, about 20–24%, while the absolute parameters of components are: M1 = 1.16, M2 = 0.39, R1 = 1.62 and R2 = 1.00 (in solar units).The O-C diagram shows an upward parabola which, under the conservative mass transfer assumption, would correspond to a mass transfer rate of dM/dt = 6.3 × 10?8M⊙/yr, matter being transferred from the less massive component to the more massive one. No cyclic, short-period variations have been found in the O-C diagram (but longer-term variations remain a possibility).  相似文献   

12.
D. Sürgit  A. Erdem 《New Astronomy》2012,17(3):336-340
This paper presents the first analysis of spectroscopic and photometric observations of the eclipsing binary star WZ Hor. Observations of the system were made at the Mt. John University Observatory in 2007. Since the light contribution of the secondary component was merely 2-3% of the total light of the system in the optical wavelengths, the radial velocity of the primary component could only be determined using the cross-correlation method. A single-lined spectroscopic orbital solution of WZ Hor was obtained, and the BVRI light curves of the system and radial velocity curve of the primary component were analysed simultaneously using the Wilson-Devinney method. The results describe WZ Hor as a reverse Algol-like binary star with a detached configuration. The following absolute parameters of the components were also derived: M1 = 1.51 ± 0.03 M⊙, M2 = 0.66 ± 0.01 M⊙, R1 = 1.62 ± 0.02 R⊙, R2 = 0.66 ± 0.01 R⊙, L1 = 4.93 ± 0.64 L⊙ and L2 = 0.09 ± 0.02 L⊙. The distance to WZ Hor was calculated as 95 ± 8 pc using distance modulus with correction for interstellar extinction, in agreement with the HIPPARCOS value.  相似文献   

13.
We have analysed the available spectra of WW And and for the first time obtained a reasonably well defined radial velocity curve of the primary star. Combined with the available radial velocity curve of the secondary component, these data led to the first determination of the spectroscopic mass ratio of the system at qspec = 0.16 ± 0.03. We also determined the radius of the accretion disc from analysis of the double-peaked Hα emission lines. Our new, high-precision, Johnson VRI and the previously-available Strömgren vby light curves were modelled with stellar and accretion disc models. A consistent model for WW And – a semidetached system harbouring an accretion disc which is optically thick in its inner region, but optically thin in the outer parts – agrees well with both spectroscopic and photometric data.  相似文献   

14.
We present a multicolor photometry for the eclipsing binary WY Hydrae, observed on four nights of 2008 December. From our new observations and Carr’s data, the photometric solutions were deduced by using the updated W–D program. The results show that WY Hya is a detached binary with a mass ratio of q = 0.970(±0.005).By analyzing the O–C curve, it is found that there exists either a continuous period increase or a cyclic variation. From Eq. (2), the orbital period of WY Hya secularly increases at a rate of dP/dt = +3.56(±0.37) × 10?7 days/yr, which may be interpreted by some mass transfer for the near-contact configuration or tidal dissipation. From Eq. (3), the period and semi-amplitude of the periodic oscillation are P3 = 95.4(±4.2) yr and A = 0d.0087(±0d.0003), respectively. This may be likely attributed by light-time effect via the presence of the assumed third body. Assumed in the coplanar orbit with the binary, the mass of the third body should be M3 = 0.18 M⊙. If the unseen additional companion exists, it will extract angular momentum from the binary system. Finally, WY Hya with high fill-out factors (i.e., f1,2 > 80%), may evolve into a semi-detached configuration.  相似文献   

15.
This paper presents the results of spectroscopic and photometric observations of the early-type W UMa system V535 Ara. New high-resolution spectra were taken at the Mt. John University Observatory in 2007. Radial velocities and spectroscopic orbital elements of the system were determined by applying KOREL spectral disentangling. The resulting orbital elements were: a1sini = 0.0047 ± 0.0001 AU, a2sini = 0.0146 ± 0.0001 AU, M1sin3i = 1.85 ± 0.01 M⊙, and M2sin3i = 0.59 ± 0.01 M⊙. The components were found to be in synchronous rotation following examination of their disentangled Hγ line profiles. Four photometric data-sets (1966 BV, 1967 BV, HIPPARCOS and ASAS) were modeled using the Wilson-Devinney method. The model describes V535 Ara as an A sub-type W UMa type eclipsing binary which has a fill out factor of 0.22 in marginal contact configuration. The simultaneous solution of light and radial velocity curves gave the following absolute parameters: M1 = 1.94 ± 0.04 M⊙, M2 = 0.59 ± 0.02 M⊙, R1 = 2.09 ± 0.03 R⊙, R2 = 1.23 ± 0.02R⊙, L1 = 18 ± 3 L⊙ and L2 = 6 ± 1 L⊙. The distance to V535 Ara was calculated as 123 ± 20 pc using distance modulus with correction for interstellar extinction.  相似文献   

16.
The eclipsing binary NN Vir is a short period system showing an EW‐type light curve. Photometric observations of NN Vir were done by Gomez‐Ferrellad & Garcia‐Melendo (1997) at Esteve Duran Observatory. We used photometric data of NN Vir for light curve analysis. The available spectroscopic data of NN Vir is new and we also used the first radial velocity data of this system obtained by Rusinski & Lu (1999) for analysis. The radial velocity and light curves analysis was made with the latest version ofWilson program(1998) and the geometric and physical elements of the system are derived. By searching the simultaneous solutions of the system, we have determined the masses and radii of the components : 1.89(M⊙) and 1.65(R⊙) for the primary component; 0.93(M⊙) and 1.23(R⊙) for the secondary component. We estimated effective temperatures of 7030(K) for the primary and 6977(K) for the secondary component. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

17.
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18.
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19.
We present CCD photometric observations of the W UMa type contact binary EK Comae Berenices using the 2 m telescope of IUCAA Girawali Observatory, India. The star was classified as a W UMa type binary of subtype-W by Samec et al. (1996). The new V band photometric observations of the star reveal that shape of the light curve has changed significantly from the one observed by Samec et al. (1996). A detailed analysis of the light curve obtained from the high-precision CCD photometric observations of the star indicates that EK Comae Berenices is not a W-type but an A-type totally eclipsing W UMa contact binary. The photometric mass ratio is determined to be 0.349 ± 0.005. A temperature difference of ΔT = 141 ± 10 K between the components and an orbital inclination of i[°] = 89.800 ± 0.075 were obtained for the binary system. Absolute values of masses, radii and luminosities are estimated by means of the standard mass-luminosity relation for zero age main-sequence stars. The star shows O’Connell effect, asymmetries in the light curve shape around the primary and secondary maximum. The observed O’Connell effect is explained by the presence of a hot spot on the primary component.  相似文献   

20.
Hipparcos photometric data for the massive O-type binary UW CMa were analysed within the framework of the Roche model. Photometric solutions were obtained for five mass ratios in the q = M2/M1 = 0.5–1.5 range. The system is found to be in a contact configuration. Independently of q, the best-fitting model solutions correspond to the orbital inclination i ～ 71° and the temperature of the secondary component T2 ～ 33500 K, at the fixed temperature of the primary T1 = 33750 K. Considering that the spectrum of the secondary is very weak, photometric solutions corresponding to the contact configuration favor the mass ratio q smaller than unity (in which case the luminosity of the secondary is smaller than that of the primary). The absolute parameters of the system are estimated for different values of the mass ratio.  相似文献   

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