Determination of physical parameters of the eclipsing binary V729 Cyg

We report new BVRI photometric observations of an eclipsing, massive binary V729 Cyg taken between 2008 and 2011. We performed light curve modeling of the new data and those available in the literature using the Wilson-Devinney code. The best fit was obtained for a contact configuration, similarly to results derived previously by other investigators. However, a huge temperature difference of about 10 000K - 12 000K was derived, inconsistent with theoretical calculations. Ruling out a possibility of V729 Cyg being a semi-detached system harbouring an accretion disk, we determined physical parameters of components

Examining eclipsing binary V729 Cygni which is a member of a star association Cyg OB 2

Praca poświęcona jest badaniu właściwości układu zaćmieniowego V 729 Cygni na podstawie obserwacji fotometrycznych, oraz odpowiedniego modelowania. W celu wykonania szczegółowej analizy sporządzono teoretyczne krzywe zmian blasku. Wzięto pod uwagę dwa modele: model z plamą i model z dyskiem. Na podstawie przeprowadzonych rozważań stwierdzono, że podanie jednoznacznej konfiguracji układu jest niemożliwe. Jednakże, najprawdopodobniej mamy do czynienia z niekołowym gazowym dyskiem akrecyjnym. W celu jednoznacznego potwierdzenia lub obalenia przedstawionych hipotez, potrzebne jest jednak przeprowadzenie dalszych obserwacji

Classification of CMEs based on their dynamics

A large set of coronal mass ejections CMEs (6621) has been selected to study their dynamics seen with the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO) field of view (LFOV). These events were selected based on having at least six height-time measurements so that their dynamic properties, in the LFOV, can be evaluated with reasonable accuracy. Height-time measurements (in the SOHO/LASCO catalog) were used to determine the velocities and accelerations of individual CMEs at successive distances from the Sun. Linear and quadratic functions were fitted to these data points. On the basis of the best fits to the velocity data points, we were able to classify CMEs into four groups. The types of CMEs do not only have different dynamic behaviors but also different masses, widths, velocities, and accelerations. We also show that these groups of events are initiated by different onset mechanisms. The results of our study allow us to present a consistent classification of CMEs based on their dynamics