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The XMM-Newton view of the yellow hypergiant IRC + 10420 and its surroundings
Gosset, E.; De Becker, M.; Hutsemékers, D.
Among evolved massive stars likely in transition to the Wolf-Rayet phase, IRC + 10420 is probably one of the most enigmatic. It belongs to the category of yellow hypergiants and it is characterized by quite high mass loss episodes. Even though IRC + 10420 benefited of many observations in several wavelength domains, it has never been a target for …
Astrophysical data mining with GPU. A case study: Genetic classification of globular clusters
Paolillo, M.; Brescia, M.; Cavuoti, S. +4 more
We present a multi-purpose genetic algorithm, designed and implemented with GPGPU/CUDA parallel computing technology. The model was derived from our CPU serial implementation, named GAME (Genetic Algorithm Model Experiment). It was successfully tested and validated on the detection of candidate Globular Clusters in deep, wide-field, single band HS…
Analysis of light curves and apsidal motion of neglected southern eclipsing binary V399 Pup
Bulut, İ.; Çiçek, C.; Bulut, A.
In this study, the Hipparcos and ASAS light curves of the eclipsing binary V399 Pup have been analyzed using the Wilson-Devinney program. The light curve analyses have found that V399 Pup is a detached binary system with eccentric orbit. The apsidal motion parameters of the system have been obtained from the O-C curve analyses. The system has been…
Ultraviolet spectral variations of FK Comae and V 1794 Cygni
Sanad, M. R.; Bobrowsky, M.
Ultraviolet spectra of FK Comae and V1794 Cygni observed with the Hubble Space Telescope Cosmic Origins Spectrograph (HST COS) and the International Ultraviolet Explorer (IUE) satellites were analyzed for the period 1981-2011. Temporal variations of line fluxes of the O I 1306 Å, C II 1336 Å, C IV 1550 Å, He II 1640 Å and Mg II k & h 2800 Å, p…
Spectral behavior of 44 (iota) Bootis and VW Cephei in the ultraviolet
Sanad, M. R.; Bobrowsky, M.
We present ultraviolet spectra of two W UMa-type binary systems, 44 (iota) Boo and VW Cep, with good coverage over their 0.268-day and 0.278-day periods, respectively, using observations obtained with the International Ultraviolet Explorer (IUE) during the period of 1978-1989 and 1978-1992. Three profiles of 44 (iota) Boo and VW Cep showing variat…
NR Peg: A new highly active semi-detached binary
Erdem, A.; Oblak, E.; Kurpińska-Winiarska, M. +1 more
This paper presents the first analysis of spectroscopic and photometric observations of the eclipsing binary star NR Peg. ELODIE Hα observations indicate that the secondary component is a chromospherically active star; however, the spectral line profiles (especially of neutral metals) of NR Peg are very wide and have a complex structure with asymm…
Ultraviolet spectral behavior of IP Peg and DW UMa in high, intermediate and low states from the HST and IUE satellites
Sanad, M. R.
Ultraviolet spectra of IP Peg and DW UMa observed with Hubble Space Telescope Space Telescope Imaging Spectrograph & Faint Object Spectrograph (HST STIS FOS) and International Ultraviolet Explorer (IUE) satellites were analyzed during the period between 1989-1994 and 1985-2004. Different profiles of two systems showing variations of line fluxe…
First identification and absolute magnitudes of the red clump stars in the Solar neighbourhood for WISE
Bilir, S.; Ak, T.; Karaali, S. +4 more
We present the first determination of absolute magnitudes for the red clump (RC) stars with the Wide-field Infrared Survey Explorer (WISE). We used recently reduced parallaxes taken from the Hipparcos catalogue and identified 3889 RC stars with the WISE photometry in the Solar neighbourhood. Mode values estimated from the distributions of absolute…
The X-ray under-luminosity of the O-type supergiants HD 16691 and HD 14947 revealed by XMM-Newton
De Becker, M.
The members of the scarce category of Of+ supergiants present properties that are intermediate between regular O-stars and Wolf-Rayet (WR) stars. Significant similarities between these transitional stars and WN-type objects are now clearly established, at least in the visible and near-infrared domains, pointing to common stellar wind pr…
An XMM-Newton view of the M 17 nebula
Mernier, F.; Rauw, G.
We present the analysis of an XMM-Newton observation of the M 17 nebula. The X-ray point source population consists of massive O-type stars and a population of probable low-mass pre-main sequence stars. CEN 1a,b and OI 352, the X-ray brightest O-type stars in M 17, display hard spectra (kT of 3.8 and 2.6 keV) consistent with a colliding wind origi…