Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg

The X-ray spectrum of SS Cyg in outburst has a very soft component that can be interpreted as the fast-rotating optically thick boundary layer on the white dwarf surface. This component was carefully investigated by Mauche (2004) using the Chandra LETG spectrum of this object in outburst. The spectrum shows broad ( ≈5 °A) spectral features that have been interpreted as a large number of absorption lines on a blackbody continuum with a temperature of ≈250 kK. Because the spectrum resembles the photospheric spectra of super-soft X-ray sources, we tried to fit it with high gravity hot LTE stellar model atmospheres with solar chemical composition, specially computed for this purpose. We obtained a reasonably good fit to the 60–125 °A spectrum with the following parameters: Teff = 190 kK, log g = 6.2, and NH = 8 · 1019 cm−2, although at shorter wavelengths the observed spectrum has a much higher flux. The reasons for this are discussed. The hypothesis of a fast rotating boundary layer is supported by the derived low surface gravity

A Jupiter-mass planet around the K0 giant HD 208897

For over 10 years, we have carried out a precise radial velocity (RV) survey to find substellar companions around evolved G,K-type stars to extend our knowledge of planet formation and evolution. We performed high precision RV measurements for the giant star HD 208897 using an iodine (I2) absorption cell. The measurements were made at T\"UB\.ITAK National Observatory (TUG, RTT150) and Okayama Astrophysical Observatory (OAO). For the origin of the periodic variation seen in the RV data of the star, we adopted a Keplerian motion caused by an unseen companion. We found that the star hosts a planet with a minimum mass of m2sini=1.40MJ, which is relatively low compared to those of known planets orbiting evolved intermediate-mass stars. The planet is in a nearly circular orbit with a period of P=353 days at about 1 AU distance from the host star. The star is metal rich and located at the early phase of ascent along the red giant branch. The photometric observations of the star at Ankara University Kreiken Observatory (AUKR) and the HIPPARCOS photometry show no sign of variation with periods associated with the RV variation. Neither bisector velocity analysis nor analysis of the Ca II and Halpha lines shows any correlation with the RV measurements

Photometric calibration of 28-cm telecsope of NCAS KFU by jointly modeling equations of transformations and the extinction

Данная работа посвящена нахождению уравнений перехода от фотометрической системы Binstr, Ginstr, Rinstr телескопа ШК-280, установленного на СКАС КФУ, в стандартную BJ , VJ , RC систему Джонсона—Казинса с применением современных численных методов. Были проведены наблюдения стандартов Ландольта поля SA110. Выполнена абсолютная фотометрия избранных звезд, оценена погрешность измерений. Построена модель перехода от заатмосферных звездных величин в стандартной системе к наблюдаемым инструментальным. С помощью метода Монте-Карло с марковскими цепями совместно определены средние за период наблюдений коэффициенты атмосферной экстинкции (0.276, 0.205, 0.159 для Binstr, Ginstr, Rinstr соответственно) и коэффициенты уравнений перехода между системами (цветовые коэффициенты 0.165, −0.120, −0.378 для B0 J , V 0 J , R0C в зависимости от (B −G)0 instr, (G−R)0 instr, (G−R)0 instr соответственно).This work is devoted to study of transformations equations between Binstr, Ginstr, Rinstr photometric system of 28-cm Schmidt-Cassegrain telescope mounted in NCAS KFU to standard Johnson—Cousins BJ , VJ , RC using modern numerical methods. Observations of Landold Standards at the SA110 region were performed. Absolute photometry of selected stars was obtained with estimatiuon of observational errors. To transform the observational data into the standart system numerical model was built with the use of Markov Chain Monte Carlo sampling. So, we found average parameters of transformations between systems (color reduction coefficients are 0.165, −0.120, −0.378 for B0 J , V 0 J , R0C in dependence of (B − G)0 instr, (G − R)0 instr, (G − R)0 instr respectievely) and medium extinction at the observational period (0.276, 0.205, 0.159 for Binstr, Ginstr, Rinstr respectievely)

Additional spectroscopic redshift measurements for galaxy clusters from the First Planck Catalogue

We present the results of spectroscopic redshift measurements for the galaxy clusters from the first all-sky Planck catalogue of the Sunyaev-Zeldovich sources, that have been mostly identified by means of the optical observations performed previously by our team (Planck Collaboration, 2015a). The data on 13 galaxy clusters at redshifts from z=~0.2 to z=~0.8, including the improved identification and redshift measurement for the cluster PSZ1 G141.73+14.22 at z=0.828, are provided. The measurements were done using the data from Russian-Turkish 1.5-m telescope (RTT-150), 2.2-m Calar Alto Observatory telescope, and 6-m SAO RAS telescope (Bolshoy Teleskop Azimutalnyi, BTA).Comment: published in Astronomy Letter

Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg

The X-ray spectrum of SS Cyg in outburst has a very soft component that can be interpreted as the fast-rotating optically thick boundary layer on the white dwarf surface. This component was carefully investigated by Mauche (2004) using the Chandra LETG spectrum of this object in outburst. The spectrum shows broad ( ≈5 °A) spectral features that have been interpreted as a large number of absorption lines on a blackbody continuum with a temperature of ≈250 kK. Because the spectrum resembles the photospheric spectra of super-soft X-ray sources, we tried to fit it with high gravity hot LTE stellar model atmospheres with solar chemical composition, specially computed for this purpose. We obtained a reasonably good fit to the 60–125 °A spectrum with the following parameters: Teff = 190 kK, log g = 6.2, and NH = 8 · 1019 cm−2, although at shorter wavelengths the observed spectrum has a much higher flux. The reasons for this are discussed. The hypothesis of a fast rotating boundary layer is supported by the derived low surface gravity

THE CBS SPECTRA INVESTIGATION AS METHOD OF THE PN CHEMICAL COMPOSITION ANALYSIS

We report the results of the investigations of chemical composition of close binaries which had gone through the stage of common envelope and which are the remnants of planetary nebular cores. High resolution spectra for different phases of orbital period of V471 Tau were taken by RTT-150 telescope and were investigated by the modified SYNTH-K program. It was found that the spectra show noticeable variability with appearance of emission components depended on the orbital period phase. For chemical composition determination the "solar" oscillator strengths for 700 lines were taken. It was found that the chemical content of V471 Tau is composite one and characterized by excess of ?-process elements in the contrast to small underabundance of iron-peak elements. The estimation of different elements excesses allows to determine their contents in planetary nebular phase