Physics / Fizik

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

Browse

Filters

2005 - 20092

Settings

Author: search.filters.author.Yakut, KadriPublisher: search.filters.publisher.EDP Sciences

Search Results

Now showing 1 - 2 of 2
  • Article
    Citation - WoS: 38
    Citation - Scopus: 37
    Close Binary and Other Variable Stars in the Solar-Age Galactic Open Cluster M67
    (EDP Sciences, 2009) Yakut, Kadri; Kalomeni, Belinda; Kalomeni, Belinda; Van Winckel, H.; Wealkens, C.; De Cat, P.; Bauwens, E.; Vuckovic, M.; Saesen, S.; Le Guillou, L.; Parmaksızoğlu, M.; Uluç, K.; Khamitov, I.; Raskin, G.; Aerts, C.; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    We present multi-colour time-series CCD photometry of the solar-age galactic open cluster M67 (NGC 2682). About 3600 frames spread over 28 nights were obtained with the 1.5 m Russian-Turkish and 1.2 m Mercator telescopes. High-precision observations of the close binary stars AH Cnc, EV Cnc, ES Cnc, the δ Scuti type systems EX Cnc and EW Cnc, and some long-period variables belonging to M67 are presented. Three full multi-colour light curves of the overcontact binary AH Cnc were obtained during three observing seasons. Likewise we gathered three light curves of EV Cnc, an EB-type binary, and two light curves of ES Cnc, a blue straggler binary. Parts of the light change of long-term variables S1024, S1040, S1045, S1063, S1242, and S1264 are obtained. Period variation analysis of AH Cnc, EV Cnc, and ES Cnc were done using all times of mid-eclipse available in the literature and those obtained in this study. In addition, we analyzed multi-colour light curves of the close binaries and also determined new frequencies for the δ Scuti systems. The physical parameters of the close binary stars were determined with simultaneous solutions of multicolour light and radial velocity curves. Finally we determined the distance of M67 as 857(33) pc via binary star parameters, which is consistent with an independent method from earlier studies.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Cyclotron Emission From Accretion Plasma Columns in Magnetic Cataclysmic Variable Stars
    (EDP Sciences, 2005) Kalomeni, Belinda; Kalomeni, Belinda; Yakut, Kadri; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    Pure cyclotron spectra of polars produced during their low accretion states are deduced. We used the working hypothesis that the cyclotron emission is produced by electrons spiraling down the dipole magnetic field lines and forming an accretion plasma column on top of the magnetic pole of a white dwarf. The velocity distribution function of electrons emitting cyclotron radiation is assumed to be a bi-Maxwellian. Since the radiating electrons in a million-Gauss magnetic field seek their respective magnetic mirrors, the perpendicular components of their velocity vectors are assumed to be greater than the parallel ones in the radiation region. This assumption implies that the cyclotron radiation is emitted more or less in the perpendicular direction (to the local magnetic field). Then we investigated the contribution of the ordinary and the extraordinary wave modes to the luminosity. The model predictions seem to be consistent with observations. We present the model cyclotron spectra of a randomly chosen polar, UZ For, as a case study.