Yazar "Michel, Raul" seçeneğine göre listele

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    Öğe
    BSN: The First Photometric Study of 10 Contact Binary Systems from the Northern and Southern Hemispheres
    (Iop Publishing Ltd, 2024) Poro, Atila; Li, Kai; Michel, Raul; Castro, Angel; Lajus, Eduardo Fernandez; Wang, Li-Heng; Coliac, Jean-Francois
    Photometric observations were made with standard filters in four observatories for 10 contact binary systems. We analyzed the orbital period variations of the systems and found that six of them show long-term changes. The increase in the orbital period of the J07, N65, and PU Vir systems is caused by mass transfer, and the reduction in the orbital period of the J05, LO Psc, and N49 systems is caused by the combination of angular momentum loss and mass transfer. The first light-curve analysis was performed with the PHysics Of Eclipsing BinariEs Python code and Markov Chain Monte Carlo. We discussed the accuracy of photometric mass ratio estimates for contact binary systems with total and partial eclipses compared to spectroscopic results. We also compared our mass ratio findings to a recent method that estimates mass ratios from the light curve's third derivative. Then, we also discussed this new mass ratio estimate method for photometric data. The systems' positions were displayed in 18 empirical parameter relationships. According to the light-curve analysis and estimation of absolute parameters, systems BE Mus, J07, J08, N49, and N65 are A subtypes, and the others are W subtypes.
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    Öğe
    Photometric and Kinematic Studies of Open Clusters Ruprecht 1 and Ruprecht 171
    (Wiley-V C H Verlag Gmbh, 2024) Cakmak, Hikmet; Yontan, Talar; Bilir, Selcuk; Banks, Timothy S.; Michel, Raul; Soydugan, Esin; Koc, Seliz
    This study outlines a detailed investigation using CCD UBV and Gaia DR3 data sets of the two open clusters Ruprecht 1 (Rup-1) and Ruprecht 171 (Rup-171). Fundamental astrophysical parameters such as color excesses, photometric metallicities, ages, and isochrone distances were based on UBV-data analyses, whereas membership probability calculations, structural and astrophysical parameters, as well as the kinematic analyses were based on Gaia DR3-data. We identified 74 and 596 stars as the most probable cluster members with membership probabilities over 50% for Rup-1 and Rup-171, respectively. The color excesses E(B-V) were obtained as 0.166 +/- 0.022 and 0.301 +/- 0.027 mag for Rup-1 and Rup-171, respectively. Photometric metallicity analyses were performed by considering F-G type main-sequence member stars and found to be [Fe/H]=-0.09 +/- 0.16 and [Fe/H]=-0.20 +/- 0.20 dex for Rup-1 and Rup-171, respectively. Ages and distances were based on both UBV and Gaia-data analyses; according to isochrone-fitting these values were estimated to be t=580 +/- 60 Myr, d=1469 +/- 57 pc for Rup-1 and t=2700 +/- 200 Myr, d=1509 +/- 69 pc for Rup-171. The present-day mass function slope of Rup-1 was estimated as 1.26 +/- 0.32 and Rup-171 as 1.53 +/- 1.49. Galactic orbit integration analyses showed that both of the clusters might be formed outside the solar circle.