Galaxies with polar rings (PRGs) are a unique class of extragalactic objects, consisting of a ring or disk of gas, stars and dust orbiting in a plane nearly perpendicular to the disk of a central galaxy. More...

According to modern views on the evolution and origin of stars, most of the stars are members of binary systems. If both components are massive enough, they eventually go supernova one by one, whereas their cores collapse, turning into black holes or neutron stars. More...

The history of star formation was successfully analyzed for the first time based on the spectra of the stellar population of dwarf galaxies of low surface brightness outside the Local Group. We have investigated the stellar population of two dwarf spheroidal galaxies KDG61 and KDG64 in the central part of a close group of galaxies M81. More...