Yazar "Ak, N. Filiz" seçeneğine göre listele

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    Öğe
    A catalogue of chromospherically active binary stars (third edition)
    (Wiley-Blackwell, 2008) Eker, Z.; Ak, N. Filiz; Bilir, S.; Dogru, D.; Tueysuez, M.; Soydugan, Esin; Bakis, H.
    The catalogue of chromospherically active binaries (CABs) has been revised and updated. With 203 new identifications, the number of CAB stars is increased to 409. The catalogue is available in electronic format where each system has a number of lines (suborders) with a unique order number. The columns contain data of limited numbers of selected cross references, comments to explain peculiarities and the position of the binarity in case it belongs to a multiple system, classical identifications (RS Canum Venaticorum, BY Draconis), brightness and colours, photometric and spectroscopic data, a description of emission features (Ca II H and K, H alpha, ultraviolet, infrared), X-ray luminosity, radio flux, physical quantities and orbital information, where each basic entry is referenced so users can go to the original sources.
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    High Resolution Coude Echelle Spectroscopy of IX Per
    (Amer Inst Physics, 2009) Ak, N. Filiz; Eker, Z.; Ak, H.; Kuecuek, I.
    High resolution (R=45033) Coude - Echelle spectra of IX Per has been obtained at TUBITAK National Observatory (TUG) of Turkey. IX Per has been known to be a single lined (SBI) spectroscopic binary having chromospheric activity. However, analyzed spectra of IX Per by KOREL disentangling method indicated that the system is a double lined (SB2) spectroscopic binary. Weaker lines from the secondary arc discovered on the decomposed spectra. A preliminary orbit indicates that the mass ratio of the system is 0.64. The light contribution of the secondary is tip to 10% in investigated spectral region. Circular orbit is sufficient to explain radial velocity variations.
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    New absolute magnitude calibrations for detached binaries
    (Wiley-V C H Verlag Gmbh, 2008) Bilir, S.; Ak, T.; Soydugan, Esin; Soydugan, Faruk; Yaz, E.; Ak, N. Filiz; Eker, Z.
    Lutz-Kelker bias corrected absolute magnitude calibrations for the detached binary systems with main-sequence components are presented. The absolute magnitudes of the calibrator stars were derived at intrinsic colours of Johnson-Cousins and 2MASS (Two Micron All Sky Survey) photometric systems. As for the calibrator stars, 44 detached binaries were selected from the Hipparcos catalogue, which have relative observed parallax errors smaller than 15% (sigma(pi)/pi <= 0.15). The calibration equations which provide the corrected absolute magnitude for optical and near-infrared pass bands are valid for wide ranges of colours and absolute magnitudes: -0.18 < (B - V)(0) < 0.91, -1.6 < M-V < 5.5 and -0.15 < (J - H)(0) < 0.50, -0-02 < (H - K-s)(0) < 0. 13, 0 < M-J < 4, respectively. The distances computed using the luminosity-colours (LCs) relation with optical (B V) and near-infrared (J H K-s) observations were compared to the distances found from various other methods. The results show that new absolute magnitude calibrations of this study can be used as a convenient statistical tool to estimate the true distances of detached binaries out of Hipparcos' distance limit. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim