Abstract: Massive star clusters are essential components of galaxies. When they form and during their early times they influence the surrounding interstellar medium with radiation, winds and supernova ejecta. This stellar feedback removes the gas out of the parent molecular cloud, star cluster expands, and in many cases it dissolves completely. Remaining globular star clusters reside in galaxy haloes. The model of massive star cluster formation as the monolithic collapse of the parent molecular cloud needs to be revisited due to discovery of multiple stellar generations of long-lived stars in globular clusters. We propose a new "cooling winds model" explaning formation of the second stellar generation out of matter that is enriched by H-burning products of the first stellar generation. Above a critical mass of the star cluster, winds form thermally unstable clumps reducing locally the temperature and pressure of the hot 10^7 K cluster wind. The matter reinserted by stars, and mass loaded in interactions with pristine gas and with evaporating circumstellar disks, accumulates in clumps that are ionized with photons produced by massive stars. We shall discuss if they may become self-shielded when they reach the central part of the cluster, or even before it during their free fall to the cluster center. We shall explore the importance of early mass loading of the stellar winds, and we shall analyse the role of additional cooling by dust produced in supernova events.

Abstract: Observations of the solar wind show pervasive presence of the non-Maxwellian kappa-distributions of electron energies characterized by a power-law high-energy tail. Theory has shown that such distributions can arise in the solar corona during impulsive heating by magnetic reconnection and also wave-particle interactions. We explored the consequences of the presence of such kappa-distributions on the optically thin spectra of the solar corona emitted in the X-rays, UV, and visible wavelengths. In particular, several line combinations allow for diagnostics of the kappa-distributions. A diagnostic from the EUV line ratios observed by Hinode/EIS space-borne spectrometer is performed and it is shown that the electron distribution can be strongly non-Maxwellian.

Abstract: High-Mass X-ray Binaries (HMXBs) are a phase in the life of some binary stellar systems that consist of a compact object (black hole or neutron star) and a massive companion (an early OB-type star). Their X-ray emission is powered by the infall of matter, provided by the massive companion, into the strong gravitational field of the compact star. The Small Magellanic Cloud (SMC) is a powerhouse of HMXB production (almost 100 systems), and due to its proximity we are able to investigate individual sources. However, we haven't yet fully characterize its HMXB population. To address that we have initiated wide spectroscopic and Halpha imaging campaigns. I will discuss our results and how the SMC HMXB population compares with that of our Galaxy.

Abstract: Mutual collisions between asteroids affect their size distribution, spins and surface morphology. Subcatastrophic collisions may be responsible for an excited asteroid rotations. We created a numerical model to investigate this hypothesis and also other effects of small collisions between asteroids. Recently, we showed that erosion caused by collisions increases the elongation of asteroid shapes on a timescale much longer than their collisional lifetime.