Yazar "Celik, E." seçeneğine göre listele

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    Öğe
    Discovery of delta Scuti variables in eclipsing binary systems II. Southern TESS field search
    (Oxford Univ Press, 2023) Alicavus, F. Kahraman; Coban, C. G.; Celik, E.; Dogan, D. S.; Ekinci, O.; Alicavus, F.
    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 & delta; Scuti variables. & delta; 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 & delta; Scuti stars in EBs. We produced an algorithm to search for detached and semidetached EBs considering three steps: the orbital period (P-orb)'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 & delta; Scuti-type oscillations, the binary variation was removed from the light curve, and residuals were analysed. Consequently, we identified 42 & delta; Scuti candidates in EBs. The P-orb, L, and M-V 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.
  • [ X ]
    Öğe
    Stokes flow in lid-driven cavity under inclined magnetic field
    (Polish Acad Sciences Inst Fundamental Technological Research, 2022) Gurbuz-Caldag, M.; Celik, E.
    STOKES FLOW IN A LID-DRIVEN CAVITY under the effect of an inclined magnetic field is studied. The radial basis function (RBF) approximation is employed to the magnetohydrodynamic (MHD) equations which include Navier-Stokes equations of fluid dynamics and Maxwell's equations of electromagnetics through Ohm's law with the Stokes approximation. Numerical results are obtained for the moderate Hartmann number (0 < M < 80) and different angles of a magnetic field (0 < alpha < pi). It is found that the increase in the Hartmann number causes the development of new vortices under the main flow due to the impact of a magnetic field. However, the type of the inclination angle (acute or obtuse) determines the location of the vortices.