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No abstract available

No abstract available

[en] By the comparative study of adjacent stellar associations in the Magellanic Clouds, we were able to follow the spatial and temporal developments of starbursts at the scales of 10 Myr and 500 pc. Most of the known S Dor type stars of the Magellanic Clouds were thus found to have a relatively old environment. We propose to revisit the current ideas on age and evolutionary status of S Dor stars (Hubble-Sandage Variables) and different subtypes of WR stars

[en] We propose that radio structures on 0.1--100 pc scales in the galactic centre radio lobe (GCL) are manifestations of magnetic activity in a central source object. The observations indicate that truly one dimensional structures occur and we hold that this is strong evidence for magnetic loops. They are generated on subpc scales and expand out to 10--100 pc. Their interaction with the 2 pc molecular torus as well as the GCL on 30--50 pc scales reproduces the observed irregular ionized and molecular emission on 2 pc scales, as well as the bridge, radio arc, and thread-like filaments on the larger ones. The Sgr A radio lobe itself (on 10 pc scales) is comprised of a system of lower energy magnetized loops which have been trapped in the molecular torus. The main thrust of this theory is that all of these exotic structures may be understood within the framework of one rather simple model

[en] VLBI observations of the compact radio structure in a sample of 65 powerful extragalactic radio sources are presented. The sources are classified as very compact, compact, asymmetric, compact double, irregular flat-spectrum, compact steep-spectrum, and lobe-dominated. Two different types of compact double source are identified. One-sided jets are found to be common features in AGN. Compact, optically thick cores are found in all objects except compact S doubles and a few steep-spectrum compact objects. No two-sided jet has yet been found in an AGN. The nuclear jets lie on the same side of the core as the large-scale jets. The nuclear jets are fairly highly polarized, with polarizations typically in the range of 1-5 percent. Superluminal motion is common in AGN and is found in all classes of object except the compact S double objects. 150 references

[en] Recent observations of the structure of the Galactic spheroid are analysed and confirm the existence of a very flattened component of the spheroid. This component contains approx. 2 per cent of the stars in the solar neighbourhood, but is not that identified in previous studies of high-velocity subdwarfs. It is distributed either in a flattened spheroid, or as an exponential perpendicular to the plane. It is photometrically distinct from the Galactic old disc, in that the spatial density distribution changes abruptly near z = 1.5 kpc. This population is therefore a spheroidal population, not a part of the old disc. (author)

[en] The formula to estimate the possibility of existence of planetary system in a star taking into account the multiplicity of star systems, is suggested. It is shown that the possibility of formation of planetary system can be estimated by Psub(ps) approximately 0.23 value. This gives the estimate of the general number of planetary systems in the Galaxy (where approximately 2x10¹¹ stars) - approximately 4.6x10¹⁰. In the radius of 10 ps 120-140 planetary systems can be expected

[en] It has recently been claimed (Malkam, 1983) that the intrinsic H-alpha/H-beta ratio for narrow line regions (NLRs) in active galactic nuclei is significantly larger than the standard case B recombination values. Here, the data assembled by Malkan are reexamined, and it is shown that the de-reddened H-alpha/H-Beta ratios are consistent with a value only slightly greater than case B, with no clear evidence for intrinsic variation from object to object. The systematic errors in the methods used are discussed, and some differences between the NLRs of Seyfert 1 and Seyfert 2 galaxies are noted. 22 references