| Abstract [eng] |
The interstellar matter in the Galaxy is concentrated in a thin layer close to the galactic plane, mostly in spiral arms. Most of the interstellar matter is in a form of atomic and molecular gas and only 1% of its mass is in a form of small (0.01 – 0.1 µm) dust grains which absorb and scatter the light of stars and cause the interstellar extinction. A part of interstellar gas and dust are in a diffuse form and fill the space with density which exponentially decreases with the distance from the galactic plane. However, in the spiral arms gigantic molecular clouds are present which play an outstanding role in the evolution of the Galaxy, since in them star forming processes take place. Molecular and dust clouds, young star clusters and associations and other star forming regions are concentrated in the Milky Way plane. However, due to gravitational and radiation interactions between the molecular clouds and the young massive stars, some fragments of spiral arms deviate from the galactic plane. One of such deviating branches from the Local (Orion) spiral arm is a huge elongated system of molecular and dust clouds located in the Cepheus constellation which is known as the Cepheus Flare. Most of the objects investigated in this dissertation belong to this branch of the Local spiral arm. The objects selected for the investigation are star forming regions in the vicinity of the reflection nebula NGC 7023, a group of dark clouds TGU 619, the young open cluster NGC 7129 and the old open cluster NGC 7142 located behind the dust cloud TGU 645. In the investigation we applied CCD photometry in the Vilnius seven color photometric system obtained with the Maksutov-type telescope of the Molėtai Observatory in Lithuania and the 1.8 meter telescope of the Vatican Observatory on Mt. Graham, Arizona. In the NGC 7023, TGU619, NGC 7129 and NGC 7142 areas we determined the run of interstellar extinction with distance and distances to the dust clouds and star forming regions. For the clusters NGC 7129 and NGC 7142 the distances, interstellar extinctions, ages and masses of stars were determined. For identification of young stellar objects and for investigation of interstellar extinction law, we have used infrared photometry in 2MASS, Spitzer and WISE systems, taking the data from the databases at CDS (Strasbourg) and NASA. The results of the investigation are published in four papers in “Baltic Astronomy” and two papers in “Monthly Notices of the Royal Astronomical Society”. |
