Yazar "Kahraman Alicavus, Filiz" seçeneğine göre listele

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    Absolute parameters of young stars: NO Puppis
    (Cambridge Univ Press, 2025) Erdem, Ahmet; Bakış, Volkan; Southworth, John; Rhodes, Michael; Kahraman Alicavus, Filiz; Budding, Edwin; Blackford, Mark G.; Kahraman Aliçavuş, Filiz
    The southern early-type, young, eccentric-orbit eclipsing binary NO Puppis forms the A component of the multiple star Gaia DR3 5528147999779517568. The B component is an astrometric binary now at a separation of about 8.1 arcsec. There may be other fainter stars in this interesting but complex stellar system. We have combined several lines of evidence, including TESS data from four sectors, new ground-based BVR photometry, HARPS (ESO) and HERCULES (UCMJO) high-resolution spectra and astrometry of NO Pup. We derive a revised set of absolute parameters with increased precision. Alternative optimal curve-fitting programs were used in the analysis, allowing a wider view of modelling and parameter uncertainties. The main parameters are as follows: 𝑀𝐴⁢𝑎 =3.58 ±0.11, 𝑀𝐴⁢𝑏 =1.68 ±0.09 (M⊙); 𝑅𝐴⁢𝑎 =2.17 ±0.03, 𝑅𝐴⁢𝑏 =1.51 ±0.06 (R⊙), and 𝑇e⁢Aa =13 300 ±500, 𝑇e⁢Ab =7 400 ±500 (K). We estimate approximate masses of the wide companions, Ba and Bb, as 𝑀𝐵⁢𝑎 =2.0 and 𝑀𝐵⁢𝑏 =1.8 (M⊙). The close binary’s orbital separation is 𝑎 =8.51 ±0.05 (R⊙); its age is approximately 20 Myr and distance 172 ±1 pc. The close binary’s secondary (Ab) appears to be the source of low amplitude 𝛿 Scuti-type oscillations, although the form of these oscillations is irregular and unrepetitive. Analysis of the 𝜆 6678 He I profile of the primary show synchronism of the mean bodily and orbital rotations. The retention of significant orbital eccentricity, in view of the closeness of the A-system components, is unexpected and poses challenges for the explanation that we discuss.
  • [ X ]
    Öğe
    The evolutionary status of chemically peculiar eclipsing binary star DV Boo
    (Natl Astronomical Observatories, Chin Acad Sciences, 2020) Kahraman Alicavus, Filiz; Alicvus, F.
    Eclipsing binary systems are unique stellar objects to examine and understand stellar evolution and formation. Thanks to these systems, the fundamental stellar parameters (mass, radius) can be obtained very precisely. The existence of metallic-line (Am) stars in binaries is noticeably common. However, the known number of Am stars in eclipsing binaries is less. The Am stars in eclipsing binaries are extremely useful to deeply investigate the properties of Am stars, as eclipsing binaries are the only tool to directly derive the fundamental stellar parameters. Additionally, the atmospheric parameters and metallicities of such binary components could be obtained by a detailed spectroscopic study. Therefore, in this study, we present a comprehensive photometric and spectroscopic analysis of the eclipsing binary system DV Boo which has a possible Am component. The fundamental stellar parameters were determined by the analysis of radial velocity and photometric light curves. The atmospheric parameters of both binary components of DV Boo were derived considering the disentangled spectra. The chemical abundance analysis was carried out as well. As a result, we showed that the primary component exhibits a typical Am star chemical abundance distribution. The fundamental stellar parameters of the binary components were also obtained with an accuracy of <1% for masses and <3% for radii. The evolutionary status of DV Boo was examined utilizing the precisely obtained stellar parameters. The age of the system was found to be 1.00 +/- 0.08 Gyr.