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Südasien, Bd. 26 Nr. 1 (2006): Großer Sprung nach vorn

Algol türü çiftler, daha önceki büyük kütleli olan bileşenin yoldaş yıldıza hızlıca kütle aktarması sonucu oluşmuş sistemlerdir. Böylesi bir kütle aktarımının ne kadar korunumlu olduğu hala bir tartışma konusudur. Kütle aktarımından önceki sistemin durumu hakkında bugünkü bileşenlerin fotosferleri çeşitli ipuçları saklamaktadır. Bu ipuçlarından en önemlisi kütle aktarımı ile yüzeye çıkan ve hâlihazırda her iki bileşeninde fotosferinde bulunan değişmiş karbon (C) ve azot bolluğudur (N). Bu çalışmada daha önce çözümlediğimiz u Her ve delta Lib sistemlerinin yanı sıra, yüksek çözünürlüklü tayfları TLS (2m) ve Mercator (1.2m) teleskoplarından yeni elde edilen, Lamda Tau sistemi tartışılacaktır. Tayfsal ayırma yöntemi ile elde edilen bileşen tayflarının bolluk analizleri, çift yıldız evrim modellerinden beklenen bolluklar ile karsılaştırılacaktır.

National Astronomical Research Institute of Thailand, Chiang Mai 50180, ThailandWe present the first results of a spectroscopic survey of southern and equatorial Algol-type eclipsing binary systems with mass-accreting pulsating components (oEA stars) using the 2.4-m Thai National Telescope (TNT) and the 10-m South African Large Telescope (SALT). The survey aims to find orbital and binary parameters and to detect the high-degree non-radial pulsations (NRPs). We report the detection of high-degree NRPs in AS Eri, WY Cet, VY Hya, GQ TrA, BD Vir, and UW Vir.

An ensemble of 50 candidate hybrid A/F-type stars from the Kepler mission was monitored during four years with the HERMES spectrograph attached to the Mercator telescope. From this survey, we obtained new radial velocities, new or improved atmospheric properties (Teff, log g, v sin i), and classified all our targets in terms of evidence for multiplicity, pulsation and/or fast rotation. An extension of 40 new candidate hybrid A- and F-type stars from the Kepler mission has been recently defined for a second survey to be performed under similar conditions. The new high-resolution spectra will be obtained with various small and medium-sized telescopes. For a number of newly detected stellar systems with good radial velocity coverage, we also computed much improved orbits by combining the radial velocities with the time delays obtained via the monitoring of the pulsation frequencies during the four years of Kepler photometry., {"references":["Balona, L. A. 2018, MNRAS, 476, 4840","Balona, L. A., Daszyńska-Daszkiewicz, J., & Pamyatnykh, A. A. 2015, MNRAS, 452, 3073","Grigahcène, A., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., et al. 2010, ApJ, 713, L192","Irwin, J. B. 1952, ApJ, 116, 211","Koubský, P., Mayer, P., Čáp, J., Žďárský, F., Zeman, J., et al. 2004, Publications of the Astronomical Institute of the Czechoslovak Academy of Sciences, 92, 37","Lampens, P., Frémat, Y., Vermeylen, L., Sódor, Á., Skarka, M., et al. 2018, A&A, 610, A17","Murphy, S. J. & Shibahashi, H. 2015, MNRAS, 450, 4475","Nemec, J. M., Balona, L. A., Murphy, S. J., Kinemuchi, K., & Jeon, Y.-B. 2017, MNRAS, 466, 1290","Raskin, G., van Winckel, H., Hensberge, H., Jorissen, A., Lehmann, H., et al. 2011, A&A, 526, A69","Reyniers, K. & Smeyers, P. 2003, A&A, 404, 1051","Shibahashi, H., Murphy, S. J., & Kurtz, D. W. 2016, IAU Focus Meeting, 29, 642","Uytterhoeven, K., Moya, A., Grigahcène, A., Guzik, J. A., Gutiérrez-Soto, J., et al. 2011, A&A, 534, A125"]}

Spectroscopic monitoring with Mercator-HERMES over the past two years reveals that MWC 314 is a massive binary system composed of an early B-type primary LBV star and a less-luminous supergiant companion. We determine an orbital period Porb of 60.85 d from optical S II and Ne I absorption lines observed in this single-lined spectroscopic binary. We find an orbital eccentricity of e=0.26, and a large amplitude of the radial velocity curve of 80.6 km/s. The ASAS V light-curve during our spectroscopic monitoring reveals two brightness minima (\Delta V~0.1 mag.) over the orbital period due to partial eclipses at an orbital inclination angle of ~70 degrees. We find a clear correlation between the orbital phases and the detailed shapes of optical and near-IR P Cygni-type line profiles of He I, Si II, and double- or triple-peaked stationary cores of prominent Fe II emission lines. A preliminary 3-D radiative transfer model computed with Wind3D shows that the periodic P Cygni line profile variability results from an asymmetric common-envelope wind with enhanced density (or line opacity) in the vicinity of the LBV primary. The variable orientation of the inner LBV wind region due to the orbital motion produces variable P Cygni line profiles (with wind velocities of ~200 km/s) between orbital phases \phi = 0.65 to 0.85, while weak inverse P Cygni profiles are observed half an orbital period later around \phi = 0.15 to 0.35. We do not observe optical or near-IR He II, C III, and Si III lines, signaling that the LBV's spectral type is later than B0. Detailed modeling of the asymmetrical wind properties of massive binary MWC 314 provides important new physical information about the most luminous hot (binary) stars such as Eta Carinae., Comment: To appear in ASP Conference Series 2012, Four Decades of Massive Star Research - A Scientific Meeting in Honor of A. F. J. Moffat, Eds. L. Drissen, C. Robert, and N. St-Louis, 11-15 July 2011, Auberge du Lac Taureau, Qu\'ebec, Canada

The National Synchrotron Radiation Research Center is constructing the Taiwan Photon Source (TPS), a 3-GeV synchroton facility. The superconducting radio frequency (SRF) cavity modules are selected as the accelerating cavities in the electron storage ring. A test area for the SRF modules is established in the RF laboratory, which includes cryogenic environment, RF transmitter, low level RF control system, and radiation shielded space. The liquid helium is transferred from the cryogenic plant in the experimental area of the Taiwan Light Source (TLS), which is not only far from the RF laboratory but also characterized by a complicated route of 205 meters. The main concerns on the cryogenic transfer are the installation difficulty, heat loss, two-phase flow, and pressure loss. Instead of a multi-channel transfer line, which would request a long installation period on radiation-restrict area, flexible cryogenic transfer lines from Nexans were chosen. The installation period was dramatically reduced to one week. With a test Dewar in the RF lab and valve boxes on both ends of the transfer lines, a long distance cryogenic transfer system was completed and proved to work functional., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan