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A serendipitous XMM-Newton observation of MACHO 104.20906.960: A dwarf nova candidate with a 2 h period
Guainazzi, M.; Nucita, A. A.; Carpano, S. +3 more
The binaries known as cataclysmic variables are particular binary systems in which the primary star (a white dwarf) accretes material from a secondary via Roche-lobe mechanism. Usually, these objects have orbital period of a few hours so that a detailed temporal analysis can be performed. Here, we present Chandra and XMM-Newton observations of a d…
Notices to investigation of symbiotic binaries IV. Optical light curves from the near-ultraviolet
Skopal, A.
The aim of this note is to reconstruct optical light curves (LC) from the near-UV fluxes of the ultraviolet spectra of symbiotic binaries during their quiescent phases. The method is based on the fact that the nebular component of radiation dominates the near-UV during quiescent phases and represents the main source of the light variability in the…
New variations of Mg II emission lines of Mira AB with HST
Sanad, M. R.; Ibrahim, Alhassan I.
This paper presents results from high resolution observations of the Mira AB binary system taken by the HST (Hubble Space Telescope) in the ultraviolet region through the period (1999-2004). By comparing the results using HST data with those obtained from the IUE (International Ultraviolet Explorer) observations through the period (1979-1995). we …
DN Bootis: A low mass-ratio W UMa-type contact binary
Selam, S. O.; Özavcı, İ.; Nelson, R. H. +2 more
New photoelectric BVR light curves and radial velocity curves were obtained for the HIPPARCOS discovery DN Boo at the TÜBİTAK 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 struct…
The massive binary HD 152218 revisited: A new colliding wind system in NGC 6231
Gosset, E.; Nazé, Y.; Rauw, G. +2 more
We present the results of an optical and X-ray monitoring campaign on the short-period massive SB2 binary HD 152218. Combining our HiRes spectroscopic data with previous observations, we unveil the contradictions between the published orbital solutions. In particular, we solve the aliasing on the period and derive a value close to 5.604 d. Our ecc…
Changes in the photospheric magnetic field associated with solar flares
Lin, Jun; Mei, Zhixing
The flare-related, persistent and abrupt changes in the photospheric magnetic field have been reported by many authors during recent years. These bewildering observational results pose a challenge to the current flare theories in which the photospheric magnetic field usually remains unchanged in the eruption. In this paper, changes in the photosph…
Light curve analyses of new eclipsing binary systems with eccentric orbits
Bulut, İ.; Demircan, O.
A photometric study of seven new eclipsing binary systems with eccentric orbits, namely, V466 Car, V493 Car, V529 Car, MN TrA, V398 Lac, V402 Lac and V821 Cas, is presented. The photometric data analyzed were taken from the Hipparcos database. The secondary minima in all systems were shifted by different amounts from the phase 0.5 giving clear evi…
The first light-curve analysis of eclipsing binaries observed by the INTEGRAL/OMC
Zasche, P.
Three Algol-type binaries in Cygnus constellation were selected for an analysis from a huge database of observations made by the INTEGRAL/OMC camera. These data were processed and analyzed, resulting in a first light-curve study of these neglected eclipsing binaries. The temperatures of the primary components range from 9500 K to 10,500 K and the …
Apsidal motion and photometric elements of the eccentric eclipsing binary KL CMa
Bulut, İ.
The Hipparcos and ASAS light curves of the recently discovered eccentric orbit binary KL CMa were analyzed by using the Wilson-Devinney program. The analysis of the light curves and all available minimum times have revealed that the system is detached, with the orbital eccentricity e = 0.131 ± 0.007, the rate of change of the longitude of periastr…
Dust envelopes of two S-type AGB stars
Yang, Xiaohong
The ISO-SWS01 spectra of two S stars, IRAS 15492+4837 and IRAS19486+3247, have been investigated with the radiative transfer code DUSTY. For the two stars, the mass-loss rates determined from DUSTY are smaller than the values derived from CO emission, which might indicate that the mass-loss rates of the two stars was higher in the past. The ∼10 &m…