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Spectroscopic observations of the interacting massive binary AQ Cassiopea
Ibanoglu, C.; Çakırlı, Ö.; Sipahi, E.
New spectroscopic observations of the double-lined eclipsing binary AQ Cas are presented. All available spectroscopic and photometric observations have been analysed for the fundamental properties of the components. Analyses show that the system consists of a massive primary with a mass of 17.63 ± 0.91 M⊙ and radius of 13.48 ± 0.64 R
Study of the late nitrogen-sequence Galactic Wolf-Rayet star WR156. Spectropolarimetry and modeling
Afanasiev, V. L.; Panchuk, V. E.; Maryeva, O. V.
For the first time spectropolarimetric observations of Wolf-Rayet star WR156 (WN8h sub-class) were conducted. Medium resolution spectropolarimetric data in the range of 3500-7200 ÅÅ were obtained at 6-m BTA telescope of Special Astrophysical Observatory RAS (SAO RAS) using recently commissioned SCORPIO-2 spectrograph. These data show that the ligh…
Elemental abundances of the supergiant stars σ Cygnus and η Leonis
Tanrıverdi, Taner
This study aims to analyse the elemental abundances for the late B type supergiant star σ Cyg and the early A-type supergiant η Leo using ATLAS9 (Kurucz, 1995; Sbordone et al., 2004), assuming local thermodynamic equilibrium (LTE). The spectra used in this study are obtained from Dominion Astrophysical Observatory and have high resolution and sign…
Preliminary results of the spectral analysis of Suzaku data of SW Ursae Majoris and BZ Ursae Majoris
Gök, F.; İkis Gün, G.; Karagül, A.
Herein, we present the preliminary results of the spectral analysis of the Suzaku data of SW Ursae Majoris (SW UMa) and BZ Ursae Majoris (BZ UMa) which were obtained in their quiescent states. The aim of this study was to analyse 0.5-6.0 keV energy range X-ray photons of the Suzaku satellite and to determine their emission mechanisms and the areas…
Early-type W UMa contact binary system: New data on V535 Ara
Özkardeş, B.; Erdem, A.
This paper presents the results of spectroscopic and photometric observations of the early-type W UMa system V535 Ara. New high-resolution spectra were taken at the Mt. John University Observatory in 2007. Radial velocities and spectroscopic orbital elements of the system were determined by applying KOREL spectral disentangling. The resulting orbi…
A critical analysis of three near-infrared photometric methods of estimating distances to cataclysmic variables
Gariety, Michael J.; Ringwald, F. A.
A critical analysis of three methods of estimating distances to cataclysmic variables (CVs) is performed. These methods, by Ak et al., Beuermann, and Knigge, all use near-infrared ( JHK or Ks) magnitudes and the Barnes-Evans relation. We compare all three methods to distances measured by trigonometric parallax by Thorstensen, with Hubbl…
The XMM-Newton slew view of IGRJ17361-4441: A transient in the globular cluster NGC 6388
Read, A. M.; Nucita, A. A.; De Paolis, F. +1 more
IGRJ17361-4441 is a hard transient recently observed by the INTEGRAL satellite. The source, close to the center of gravity of the globular cluster NGC 6388, quickly became the target of follow-up observations conducted by the Chandra, Swift/XRT and RXTE observatories. Here, we concentrate in particular on a set of observations conducted by the XMM…
Stellar contents and star formation in the young cluster Stock 18
Pandey, J. C.; Sagar, Ram; Bhatt, Himali
We have carried out deep (V ∼ 21 mag) UBVRI photometric study of the star cluster Stock 18. These along with archival Infrared data have been used to derive the basic cluster parameters and also to study the star formation processes in and around the cluster region. The distance to the cluster is derived as 2.8 ± 0.2 kpc while its age is estimated…
Running waves observed by Hinode
Liang, H. F.; Yang, W. G.; Ma, L. +1 more
High cadence (up to 9.6 s) intensity images of a sunspot within the active region NOAA 10953 were obtained by the SOT onboard Hinode with the line H α 6563 Å on April 30, 2007. The running difference images show that running waves periodically appear within the sunspot umbra and propagate outward forming full circles or partial arcs. The propagati…
New eccentric eclipsing binary in triple system: SY Phe
Zasche, P.
Analyzing available photometry from Hipparcos, ASAS, Pi of the sky and Super WASP, we found that the system SY Phe is a detached eclipsing binary with similar components and orbital period about 5.27089 days. It has a slightly eccentric orbit, however the apsidal motion is probably very slow. The system undergoes an additional photometric variatio…