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Sadiye Cakmak Jameel-Un Nabi Tahsin Babacan Cevad Selam 《Astrophysics and Space Science》2014,352(2):645-663
The Gamow–Teller (GT) transition is inarguably one of the most important nuclear weak transitions of the spin-isospin στ type. It has many applications in nuclear and astrophysics. These include, but are not limited to, r-process β-decays, stellar electron captures, neutrino cooling rates, neutrino absorption and inelastic scattering on nuclei. The quasiparticle random phase approximation (QRPA) is an efficient way to generate GT strength distribution. In order to better understand both theoretical systematics and uncertainties, we compare the GT strength distributions, centroid and width calculations for \({^{40\mbox{--}60}\mathrm{Ti}}\) isotopes, using the pn-QRPA, Pyatov method (PM) and the Schematic model (SM). The pn-QRPA and SM are further sub-divided into three categories in order to highlight the role of particle-particle (pp) force and deformation of the nucleus in the GT strength calculations. In PM, we study only the influence of the pp force in the calculation. We also compare with experimental results and other calculations where available. We found that the inclusion of pp force and deformation significantly improves the performance of SM and pn-QRPA models. Incorporation of pp force leads to pinning down the centroid value in the PM. The calculated GT strength functions using the pn-QRPA (C) and SM (C) models are in reasonable agreement with measured data. 相似文献
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List of forthcoming papers 相似文献
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B. Albayrak G. Djurašević S. Selam M. Yilmaz S. Erkapić O. Aksu T. Tanriverdi 《Astrophysics and Space Science》2005,296(1-4):293-296
BVR light curves of the recently discovered eclipsing binary V351 Peg were studied to derive the preliminary physical parameters
of the system. The light curves were obtained at the TüBİTAK* – Turkish National Observatory (TUG) during three nights in
August, 2003. The solutions were made using Djurašević’s inverse problem method. V351 Peg is a system in an overcontact configuration
(f
over∼ 21 %) with a relatively small temperature difference between the components ΔT ≈ 20 K. The results suggest a significant mass and energy transfer from the more massive primary onto the less massive secondary.
The hot area on the less massive star, near the neck region, can be considered as a consequence of this mass and energy exchange
between the components through the connecting neck of the common envelope.
TüBİTAK: The Scientific and Technical Research Council of Turkey. 相似文献
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S. O. Selam E. M. Esmer H. V. Şenavcı E. Bahar O. Yörükoğlu M. Yılmaz Ö. Baştürk 《Astrophysics and Space Science》2018,363(2):34
In this study, we have performed simultaneous solutions of light and radial velocity curves of two eclipsing binary systems, V566 Oph and V972 Her. We observed both systems spectroscopically with a very recently installed spectrograph on the 40 cm telescope, T40, located in Ankara University Kreiken Observatory (AUKR), for the first time. We made use of the photometric data from the Hipparcos satellite for V972 Her, while we obtained the photometric observations of V566 Oph by using the 35 cm telescope, T35, located also in our observatory campus. We derived the absolute parameters for both systems and discussed their evolutionary states. In addition to the simultaneous analysis, we have also analyzed the change in mid-eclipse times for V566 Oph, and found cyclic variations, for which we have discussed light-time effect and magnetic activity as their potential origin, superimposed on a secular change due to a mass transfer between the components of the binary. 相似文献
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Z. Aslan I. F. Bikmaev É. A. Vitrichenko R. I. Gumerov L. A. Dembo S. F. Kamus V. Keskin U. Kiziloglu M. N. Pavlinsky L. N. Panteleev N. A. Sakhibullin S. O. Selam R. A. Sunyaev I. Khamitov A. L. Yaskovich 《Astronomy Letters》2001,27(6):398-403
The AZT-22 telescope installed in Turkey (Antalia) was aligned and tested on stars by the Hartmann method. The rms normal deviation of an equivalent optical system is 0.040±0.016 µm. The circle of confusion is 0.40±0.04 arcsec in diameter at a 50% energy level. 相似文献
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This study concerns the long-term monitoring of the secular variation character in the orbital period of some short-period eclipsing binaries observed at the Ankara University Observatory. Among the systems of our observing list are CK Boo, V502 Oph and V836 Cyg that show long-term secular variations in their orbital periods. We use classical O-C diagram analysis technique as a tool to reveal the character of the period variations of these binary systems. 相似文献
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New photoelectric BVR light curves and radial velocity curves were obtained for the HIPPARCOS discovery DN Boo at the TÜBİTAK1 National Observatory of Turkey (TUG) and Dominion Astrophysical Observatory (DAO), respectively, to determine physical nature of the variable. The character of the obtained light curves and double-lined spectroscopic structures in the obtained spectra are revealed that DN Boo is a genuine EW type eclipsing binary. During the analysis of our new observations a simultaneous solution were derived for the photometric and spectroscopic data by using the Wilson–Devinney code and orbital parameters with absolute dimensions of the system were determined for the first time. Finally, the importance of very low mass-ratio contact binaries in the late stages of close binary evolution was discussed. 相似文献