Sun Solar System

   Subject of study are processes in the Solar atmosphere leading to the appearance of active structures – prominences and spots. The department participates in the European organization for joint observations of the Sun (JOSO) and in programs for coordinated ground-based and orbital observations of the Sun in the framework of the project SOHO.
   Studies of the Solar System focus on the evolution of small bodies, physical and chemical properties and processes in comets, rotational characteristics of asteroids. Research in this field is based on imaging, spectral and photometric observations and positional measurements of asteroids and comets.

   Main subject of our studies are stars and the systems they build. The ultimate goal of these research activities is to gain new knowledge about the processes, phenomena and physical laws that characterize the key phases of stellar evolution – from the very early stages of star formation till the full exhaustion of thermonuclear fuel in stellar cores.
We study:
   -Physical characteristics of hot, massive, high luminosity stars and the dynamical parameters of stellar winds that accompany their evolution;
   -Chemical composition of stellar atmospheres and its variations due to the influence of circumstellar matter or tidal interactions in binary systems;
   -Processes of mass transfer, formation and development of accretion discs in close binary systems with compact component;
   -Dynamics and physical characteristics of sub-stellar systems - objects with extremely low luminosity, and planetary systems that orbit stars other than our Sun;
   -Characteristics of stellar activity we observe in stars and stellar systems, which is typical for early stages of stellar evolution;
   -Manifestation of stellar magnetism and the role that magnetic fields play in processes that feature the late stages of stellar evolution.

   Physical processes and chemical abundance in galaxies, systems of galaxies and the Universe are investigated. Photometry and Surface photometry of normal and active galaxies and galaxies in Voids are carried out.
    Disk profiles and starformation in galaxies are investigated. Structures of galaxies and clusters of galaxies are searched. Some catalogs of the most massive structures are compiled and the large scale structure in the Universe is studied.
   Primordial nucleosynthesis and chemical evolution of the light elements in the presence of neutrino oscillations is analysed. Cosmological constraints on oscillation parameters are obtained. Different baryogenesis scenarios are investigated. Possibilities of antimatter in the Universe are studied.

   A database for wide astronomical photographic observations is created. (http://skyarchive.org). The projects: Bulgarian Virtual Observatory and Bulgarian GRID computer network and it astronomical applications are developed.
   Handbooks on Using of Virtual Observatory, The GRID computer network and The database - reference tools for working with them are in preparation.