Yazar "Yildirim, Muhammed Faruk" seçeneğine göre listele

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    CN Andromedae: a shallow contact binary with a possible tertiary component
    (Natl Astronomical Observatories, Chin Acad Sciences, 2019) Yildirim, Muhammed Faruk; Alicavus, Fahri; Soydugan, Faruk
    In this study, new photometric observations of shallow contact binary CN Andromedae (CN And) were performed and multi-color (BV R) CCD light curves (LCs) were obtained. Simultaneous analysis of new LCs and published radial velocity (RV) data reveals that the system is an early contact binary in which both components have recently filled their inner Roche lobes. Asymmetric LCs were modeled by a dark spot on the primary component and a hot spot on the secondary component that probably resulted from magnetic activity and mass transfer, respectively. Modeling of LCs and RV data allows us to estimate the following absolute parameters: M-1= 1.40 +/- 0.02 M-circle dot, M-2 = 0.55 +/- 0.01 M-circle dot, R-1 = 1.45 +/- 0.02 R-circle dot and R-2 = 0.94 +/- 0.02 R-circle dot. A decreasing orbital period with a rate of dP/dt = -1.5 x 10(-7) d yr(-1) can be seen as evidence that the system is evolving into a contact binary with higher contact degree. Cyclic oscillation of the O - C data was interpreted by the Applegate mechanism and light-time effect due to an unseen component around the close binary system. The hypothetical third component is probably a fully convective red dwarf star with a minimal mass of 0.1 M-circle dot. CN And is at the early phase of the contact stage of its evolution and is an interesting example for studying the formation and evolution of close binaries.
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    Investigation of Orbital Period Changes of Selected Contact Binaries
    (Amer Inst Physics, 2016) Yildirim, Muhammed Faruk; Soydugan, Faruk
    In this study, we investigated orbital period changes of three contact binaries DK Cyg, VW Boo and CV Cyg. From O-C analysis, it was found that DK Cyg indicates orbital period increase, whereas the periods of CV Cyg and VW Boo are decreasing. For DK Cyg, mass transfer from less massive component to more massive one was used to explain the variation in the period. On the other hand, the O-C changes of CV Cyg and VW Boo were clarified using the assumption of mass transfer from more massive component to less massive one. In addition, period variation in cyclic form are also seen for VW Boo and DK Cyg. Assuming the periodic variations of these systems caused by an additional component around the binary, we calculated the basic properties of the possible unseen component in the eclipsing pairs.
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    Photometric Study of a arginal Contact Binary SY Hor
    (Amer Inst Physics, 2017) Yildirim, Muhammed Faruk; Soydugan, Faruk
    In this study, we present light curve analysis of a southern contact binary SY lior. Photometric parameters of the system and its components are derived using the Wilson and Devinney code based on the data taken from the SuperWASP public data archive. Photometric solutions indicate that SY Hai is a marginal contact binary system with a mass ratio of q = 1.59 and a contact degree of f = 6%.