This paper reports on some consequences of a comparison between model calculations of the S-component solar radio emission and observations of active regions at different wavelengths in the microwave range. Calculations of the transfer of the Scomponent emission were carried out on the base of horizontally averaged semi-empiricalv models of the solar atmosphere above sunspots and plage regions consistent with optical and EUV observations and account for Coulomb bremsstrahlung and gyromagnetic emission in dipole-like or
force-free extrapolated magnetic field configurations,
While the mean characteristics are quite in accordance, discrepancies between observations and calculation arise mainly with respect to fine structures, Considering such discrepancies, (i) possible reasons for an obvious lack of observed ring structures of S-component sources above sunspots are discussed. (ii) Subtelescopic fine structures in plage regions are predicted whereas bright plage elemente are assuraed to be embedded in a quasi-quiet background. (iii) Different kinds of loop emissions are considered, among them strange cases of persistent "hot" loop emission connected with emerging magnetic flux regions.
In tne last few decades new observational techniques have provided a wealth of physical information on several hundreds of asteroids. These objects are no longer seen as pointlike bodies
mainly interesting as a 'dynamical zoo', but have become small 'worlds' with known sizes, gross shapes, surface compositions, rotational properties and collisional histories. The diversity of these 'worlds' 3 is astonishing: they range in size from less than 1 to 10^3 km, in spin period from a few hours to many days, in shape from nearly spherical to very elongated and/or irregular, in surface reflectivity from about 0.02 .to 0.4, in composition from metal-rich and silicate rocks to volatile-rich carbonaceous assemblages. Of course there are many peculiar objects: asteroids with surface patches of different brightness and colour; bodies, which have suffered internal heating and have developed a core-mantlecrust
structure; asteroids converted by catastrophic impacts into gravitationally bound 'piles of rubble'; objects with triaxial equilibrium figures or splitted into binary systems; outer-belt
asteroids whose spectrophotometric properties are very much alike those of cometary nuclei. This paper reviews some of these recent findings, which are currently being interpreted in the frame of
complex theoretical models for the formation and evolution of orbiting and collisionally interacting bodies.
Introduction: There is a couple of topics I intend to touch in this presentation. Firstly I would like to remind some historical milestones in the development of solar observations in Wroclaw. Secondly, to introduce the main solar instruments of the Astronomical Institute of Wroclaw University (A.I.). Thirdly, to present some results of the prominence and flares investigations, callng at the same time attention to a high spatial resolution of our observations.
Since its recovery in 1982, Comet Halley has been the focus of an unparalleled global scientific effort of exploration. Remote and
in-situ measurements were conducted from the ground, from Earth orbit, from Venus orbit, from interplanetary space, and from the comet itself. Many discoveries, such as the presence of an unexpectedly large and dark nucleus or the abundance of organic presence of organic material, have led to major changes in our ideas about the general nature of comets. In this report, results of various studies are summarized.
The spectra of three surges observed on September 20 and October 2, 1979 havebeen analysed. Rotational velocities have been evaluated for the wide range of heights above the chromosphere. The obtained results show that the rotational velocity decreases from above a hundred km/s at the surge bases to tens km/s at the surge tops. Generally, this tendency is independent of the surge evolution stage.
Historical comments about identification of solar X-emission of various events and recent examples, especially of long-range emission from active regions, are presented
It is generally known that intensity of the 530.3 nm coronal line depends on tho solar aetivity. The proposed coronal index /Cl/ represents the|530-g nm line irradiance from the whole corona as it seen from the Earth in W8r“^xl0^ . The Cl is derived from daily measured intensities around the disn of the Sun. Maximum
values of the Cl were observed in the second half of the year 1981, just before a deep decrease in the Wolf´s number. Monthly average values of the Cl in the cycle 21 vary from 1,64 to 18,93. The rough comparison of the Cl with similar indices of the UV emissions shows a relative good agreement.
Observations of the total radio flux of the Sun are presented for the period 1962-1986, ciovering two 11-year cycles of solar activity, -i.e. nos 20 and 21. Daily averages of the radio fluxes for the period in question are used for graphical and numerical representation. The minimum values fo the total radio flux of the Sun of wavelength 115 cm (260 MHz), corresponding to the solar activity minima in 1964, 1976 and 1986 are given.