Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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Author: search.filters.author.Kalomeni, BelindaSubject: search.filters.subject.Fundamental parameters

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Close Binary System Go Cyg
    (Elsevier Ltd., 2012) Ulaş, Burak; Kalomeni, Belinda; Keskin, Varol; Köse, O.; Yakut, Kadri
    In this study, we present long term photometric variations of the close binary system GO Cyg. Modelling of the system shows that the primary is filling Roche lobe and the secondary of the system is almost filling its Roche lobe. The physical parameters of the system are M1 = 3.0 ± 0.2M ⊙, M2 = 1.3 ± 0.1M⊙, R 1 = 2.50 ± 0.12R⊙, R2 = 1.75 ± 0.09R⊙, L1 = 64 ± 9L ⊙, L2 = 4.9 ± 0.7L⊙, and a = 5.5 ± 0.3R⊙. Our results show that GO Cyg is the most massive system near contact binary (NCB). Analysis of times of the minima shows a sinusoidal variation with a period of 92.3 ± 0.5 yr due to a third body whose mass is less than 2.3M⊙. Finally a period variation rate of -1.4 × 10-9 d/yr has been determined using all available light curves.
  • Article
    Citation - WoS: 13
    Citation - Scopus: 8
    Marginally Low Mass Ratio Close Binary System V1191 Cyg
    (Elsevier Ltd., 2012) Ulaş, B.; Kalomeni, Belinda; Keskin, Varol; Köse, O.; Yakut, Kadri
    In this study, we present photometric and spectroscopic variations of the extremely small mass ratio (q ≃ 0.1) late-type contact binary system V1191 Cyg. The parameters for the hot and cooler companions have been determined as Mh = 0.13 (1) M⊙, Mc = 1.29 (8) M ⊙, Rh = 0.52 (15) R⊙, Rc = 1.31 (18) R⊙, Lh = 0.46 (25) L⊙, Lc = 2.71 (80) L⊙, the separation of the components is a = 2.20 (8) R⊙ and the distance of the system is estimated as 278 (31) pc. Analyses of the times of minima indicates a period increase of dPdt=1.3(1)×10-6days/yr that reveals a very high mass transfer rate of dMdt=2.0(4)×10-7M⊙/yr from the less massive component to the more massive one. New observations show that the depths of the minima of the light curve have been interchanged. © 2011 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 28
    Citation - Scopus: 28
    Basic Physical Properties of the Low-Temperature Contact Binary System V781 Tau and the Near-Contact Binary System V836 Cyg
    (Oxford University Press, 2005) Yakut, Kadri; Ulaş, Burak; Kalomeni, Belinda; Gülmen, Ömür
    We present a detailed photometric study of the low-temperature contact binary V781 Tau, and the near-contact binary V836 Cyg. We have combined the parameters obtained from the light-curve analysis with those found by the spectral studies and we have determined the orbital and physical parameters of the stars. We have collected the times of the mid-eclipses obtained so far and combined with the times obtained in this study. By analysing all these data we determined the mass transfer rate from the massive star to the less massive one for V781 Tau, and from the less massive component to the massive one in the case of V836 Cyg. Finally, we have compared the results obtained for V781 Tau and for V836 Cyg with similar systems.