Yazar "Ozkardes, Burcu" seçeneğine göre listele

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    Öğe
    New Spectroscopic Solution of the Eclipsing Binary HX Vel A
    (Astronomical Soc Pacific, 2015) Surgit, Derya; Erdem, Ahmet; Ozkardes, Burcu; Butland, Roger; Budding, Edwin
    We present a preliminary analysis of new spectroscopic observations of the southern binary HX Vel A. High-resolution spectroscopic observations were made at the Mt. John University Observatory in 2014. Radial velocities for HX Vel A were determined from the Gaussian profile-fitting method. The Keplerian radial velocity model gives the close binary mass ratio as 0.57 +/- 0.06. The resulting orbital elements are ai sin i = 0.0086 +/- 0.0003 au, a(2) sin i = 0.0151 +/- 0.0003 au, M-1 sin(3) i = 0.887 +/- 0.046 M-circle dot, and M-2 sin(3) i = 0.504 +/- 0.032 M-circle dot.
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    Spectroscopic and photometric investigation of some potentially chemically peculiar ? Scuti stars
    (Oxford Univ Press, 2025) Kahraman Alicavus, Filiz; Alicavus, Fahri; Ozkardes, Burcu; Celik, Eda
    Investigating chemically peculiar pulsating stars is crucial for understanding the pulsation driving mechanism in detail. To reveal the true peculiarity properties of stars, detailed spectroscopic analysis is essential. Therefore, in this study, we focused on delta Scuti stars previously identified as chemically peculiar but which needed comprehensive updated spectroscopic analysis to uncover their chemical abundance structure. We selected 10 targets which have publicly available high-resolution spectroscopic and photometric data. Performing spectral analyses, we determined the spectral classification, atmospheric parameters, and detailed chemical abundance distributions of the selected stars. The pulsation properties were also analyzed using TESS data, and pulsation modes for the highest amplitude pulsation frequencies were derived. We estimated the masses and ages of the targets using the evolutionary tracks and isochrones. As a result of our study, we show that only three targets exhibit chemical peculiarity: AU Scl and FG Eri as metallic A (Am) stars, and HZ Vel as a lambda Bootis. However, others were found to be chemically normal stars. This study show us the importance of chemical abundance analysis in the classification of chemical peculiar stars.
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    Öğe
    V410 Puppis: A useful laboratory for early stellar evolution
    (Oxford Univ Press, 2022) Erdem, Ahmet; Surgit, Derya; Ozkardes, Burcu; Hadrava, Petr; Rhodes, Michael D.; Love, Tom; Blackford, Mark G.
    New spectrometric (HERCULES) and ground-based multicolour photometric data on the multiple star V410 Puppis are combined with satellite photometry (HIPPARCOS and TESS), as well as historic astrometric observations. Absolute parameters for V410 Pup Aab are derived: M-Aa = 3.15 +/- 0.10, M-Ab = 1.83 +/- 0.08 (M-circle dot); R-Aa = 2.12 +/- 0.10, R-Ab = 1.52 +/- 0.08 (R-circle dot); a = 6.57 +/- 0.04 R-circle dot; T-Aa = 12500 +/- 1000, T-Ab = 9070 +/- 800(K), and photometric distance 350 +/- 10 (pc). We report the discovery of a low-amplitude SPB variation in the light curve and also indications of an accretion structure around V410 Pup B as well as emission cores in V410 Pup C. We argue that V410 Pup is probably a young formation connected with the Vela 2 OB Association. The combined evidence allows an age in the range 7-25 Myr from comparisons with standard stellar evolution modelling.