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Öğe Absolute parameters of detached binaries in the southern sky - III: HO Tel(Elsevier Science Bv, 2017) Surgit, D.; Erdem, A.; Engelbrecht, C. A.; van Heerden, H. P.; Manick, R.We present the first radial velocity analysis of the southern eclipsing binary star HO Tel, based on spectra obtained at the South African Astronomical Observatory in 2013. The orbital solution of this neglected binary gave the quite large spectroscopic mass ratio of 0.921(+/- 0.005). The V light curve from the All Sky Automated Survey (ASAS) and Walraven five-colour (WULBV) photometric light curves (Spoelstra and Van Houten 1972) were solved simultaneously using the Wilson-Devinney code supplemented by the Monte Carlo search method. The final photometric model describes HO Tel as a detached binary star where both component stars fill about three-quarters of their Roche limiting lobes. The masses and radii were found to be 1.88(+/- 0.04) M-circle dot, 2.28(+/- 0.15) R-circle dot and 1.73(+/- 0.04) M-circle dot, 2.08(+/- 0.16) R-circle dot for the primary and secondary components of the system, respectively. The distance to HO Tel was calculated as 282(+/- 30) pc, taking into account interstellar extinction. The evolution case of HO Tel was also examined. Both components of the system are evolved main-sequence stars with an age of approximately 1.1 Gy, when compared to Geneva theoretical evolution models. (C) 2017 Elsevier B.V. All rights reserved.Öğe Absolute parameters of eclipsing binaries in Southern Hemisphere sky - II: QY Tel(Elsevier Science Bv, 2016) Erdem, A.; Surgit, D.; Engelbrecht, C. A.; van Heerden, H. P.; Manick, R.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-circle dot, 1.74 (+/- 0.15) R-circle dot and 1.44 (+/- 0.09) M-circle dot, 2.70 (+/- 0.16) R-circle dot 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. (C) 2016 Elsevier B.V. All rights reserved.Öğe First Spectroscopic Solutions of Two Southern Eclipsing Binaries: HO Tel and QY Tel(Astronomical Soc Pacific, 2015) Surgit, D.; Erdem, A.; Engelbrecht, C. A.; van Heerden, P.; Manick, R.We present preliminary results from the analysis of spectroscopic observations of two southern eclipsing binary stars, HO Tel and QY Tel. The grating spectra of these two systems were obtained at the Sutherland Station of the South African Astronomical Observatory in 2013. Radial velocities of the components were determined by the Fourier disentangling technique. Keplerian radial velocity models of HO Tel and QY Tel give their mass ratio as 0.921 +/- 0.005 and 1.089 +/- 0.007, respectively.