Bronisław Rudak (NCAC, Toruń)
Radosław Smolec (Copernicus Astronomical Center, Warsaw)
I will discuss the discovery of the first BL Her star showing the period doubling effect and present its nonlinear modelling. I will also discuss the models in which periodic and chaotic modulation of pulsation was found. Although the effect is not observed in any BL Her star, it is a common property of their lower luminosity siblings - RR Lyrae stars showing the Blazhko effect. These models provide a support for a radial resonance model proposed recently to explain the Blazhko mystery.
Claes Fransson (Swedish Natl. Comm. for Astronomy )
SN 1987A is arguably the most important supernova in our life time. I will summarize the main discoveries during the first years after the explosion and then emphasize more recent developments. This includes the understanding of the core collapse, the ejecta structure, nucleosynthesis and interaction with the circumstellar ring. I will also discuss the relation of this somewhat peculiar supernova with other core collapse supernovae.
Mirosław Giersz and Arkadiusz Hypki (NCAC, Warsaw)
We will discuss a major upgrade of Monte Carlo code which previously used in many studies of dense stellar clusters. We outline steps needed in to calibrate the results of MOCCA code against N-body simulations for large N systems. The MOCCA code incorporates direct FewBody integrator for small N interactions and a new treatment of the escape process. We will also discuss the first results of the studies of Blue Stragglers' properties in dynamically evolving stellar clusters, their channels of formation and processes leading to changes of their types. The MOCCA code is at present the most advanced code for simulations of a real star clusters.
