Einfluß verbesserter Deklinationswerte auf die PZT-Breiten-bestimmungen in Potsdam (Mitteilungen des Zentralinstituts für Physik der Erde Nr. 1027)

The results of latitutde determinations with the PZT at Potsdam observatory in the years 1972–78 were used to improve the declinations of the observed stars. The latitude determinations were re-reduced with the calculated corrections of declinations in the system of the new catalog. The obtained results show a substantially better agreement and a higher stability with respect to the BIH system than the results in the system of the hitherto used star catalog.     

The New Programme of Observations with the DANJON Astrolabe of Potsdam Geodetic-Astronomical Observatory (Mitteilungen des Zentralinstituts für Physik der Erde,Nr. 821)

The old programme of observations (cf. Beobachtungsergebnisse 1964 and Astronomische Zeit- und Breitenbestimmungen 1965, 1) was modified. The conditions described in Instruction (1956) were used again. As previously (cf. Beobachtungsergebnisse 1964), the stars were selected in respect of the derivation of corrections to the co-ordinates of the stars. The new programme, which has been in use since September of 1978, can be used up to the year 2000.     

Astronomische Längen-und Breitendifferenzen der Basisobservatorien Irkutsk,Potsdam und Simeiz (Mitteilungen des Zentralinstituts für Physik der Erde,Nr. 1180)

In 1980/1981 astronomical observations using a carried DANJON -astrolabe were made at Irkutsk, Potsdam and Simeiz stations in order to determine the longitude and latidute differences. — It is informed about the observations made and the analysis of the results obtained. The formulas required for the astronomical longitude and latitude determination are indicated. Subsequent calculation of the weighted mean serves to stepwise condence the values and, at the same time, to examine them for systematic groupe differences and personal errors. Finally the longitude and latitude differences are derived taking into account the observers' personal equations. Their accuracies range from ±0.0020 s to ±0.0028 s and from ±0.013”︁ to ±0.017”︁, respectively. Russian text ingnor     

The outer core rotation about an inclined axis from geomagnetic secular variations (Mitteilungen des Zentralinstituts für Physik der Erde,Nr. 1832)

Non-axisymmetric motions of the outer core of the Earth are important for the dynamo problem and the excitation of the decade variations of the polar motion. The components of the vector of a rigid rotation of the outer core about an inclined axis were estimated by a first-order approximation of the frozen- field theory of the geomagnetic secular variation from 1903.5 to 1975.5. The trends and quasi-periodic constituents of these quantities were computed. It was shown that the position and time behaviour of the rotational pole of the outer core differ considerably from the well-know co-ordinates of the dipole axis. Some periods of the equatorial components of the rotational vector are comparable with those of the axial component previously derived for a pure axial rotation. Additionally, the time behaviour of the pole path shows events like the well-known Markowitz wobble but naturally with other extent. These and other results suggested that the investigations are worth to be continued in future by some physical interpretations.     

The periodic variations of the core drift rate: global and zonal motions (Mitteilung des Zentralinstituts für Physik der Erde,Nr. 1746)

Toroidal zonal motions at the top of the Earth's core were computed from the observed secular variation and investigated with regard to their time dependence. Previously derived results for a pure westward drifting core could be re-examined. Additionally, the well-known 66.7 years period was found to be an oscillation of the zonal velocity field of third degree. With respect to periodic constituents, the total magnetic core-mantle coupling torque according to the zonal motions is comparable with that derived for a pure westward drifting core. Some differences in period lengthes and amplitudes do not remove previously stated differences between the spectra of the magnetic and mechanical torques on principle.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV) (BAV-Mitteilungen Nr. 29)

In this 12th compilation of BAV results of observations are given from the years 1976 and 1977 for 231 observed minima of 58 eclipsing binaries, 108 maxima of 25 RR Lyrae stars, four maxima of four δ Cephei stars, four maxima of one δ Scuti star and 182 results of 23 longperiodic, semi-regular, irregular and RV Tauri stars.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV) (BAV-Mitteilungen Nr. 31)

In this 13^th compilation of BAV results of observations are given from the years 1978 and 1979 for 172 observed minima of 75 eclipsing binaries, 70 maxima of 17 RR Lyrae stars, 309 results of 93 Mira stars and 90 results of 19 longperiodic, semiregular irregular and RV Tauri stars and 6 results of 5 eruptive variable stars.     

Rechnergesteuerte schnelle Photometrie am Beispiel der Bedeckung von 57 Orionis durch den Mond. II. (Mitteilungen der Universitäts-Sternwarte zu Jena Nr. 155)

The needed formulae for the reduction of lunar occulations are presented and used for the treatment of the occultation data of 57 Orionis. A computing method for the determination of the object profile is given and the influence of noise is discussed. The results for the spectroscopic binary 57 Orionis cannot be explained by the parameters published.     

Rechnergesteuerte schnelle Photometrie am Beispiel der Bedeckung von 57 Orionis durch den Mond. I. (Mitteilungen der Universitäts-Sternwarte zu Jena Nr. 154)

For high speed photometric observations the photoelectric system was modified. The supplement of the interpreting programming language permits measurements down to 1 ms integration time with an overall measuring time of at least 4 s. The application in the case of lunar occultations is described and an outlook of the data reduction treatment is given.     

On Measuring the Dynamical Age of Clusters of Galaxies (Mitteilungen der Universitätssternwarte zu Jena Nr. 139) Universitätssternwarte and Zentralinstitut für Astrophysik der Akademie der Wissenschaften der DDR With 4 Figures

The method for measuring the dynamical age of n-body systems proposed by S. von HOERNER (1976) is applied to clusters of galaxies. The modulus of evolution W characterizing quantitatively the dynamical state of the cluster was determined for several objects. It turns out that the Virgo cluster is one of the dynamically youngest clusters.     

On the Widths of Dust Layers in Galaxies (Mitteilungen der Universitätssternwarte Jena Nr. 156)

From prints of the Palomar Observatory Sky Survey the widths of the equatorial dust layers of a sample of 39 galaxies seen on edge are obtained to be in the range 500 ≤ D ≤ 1600 pc. The width of a dust layer seems to be correlated with the luminosity of the galaxy. The dust lanes of field galaxies are obviously broader than those of the members of the Virgo cluster. This result may be interpreted as a dust deficiency caused by stripping of interstellar matter resulting from galactic collisions and interaction of the galaxies with the intracluster medium.     

Mass loss from very young massive stars (Mitteilungen der Universitäts-Sternwarte zu Jena Nr. 172)

A very important property of very young and massive stars (BN objects) is their intensive mass loss. We describe the main methods to derive the mass loss rates. Available observations are used to characterize the ionized stellar winds and the CO flows. The results are confronted with theories describing the anisotropic mass loss.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für veränderliche Sterne e. V. (BAV)

In this 8th compilation, the following results of observations are given: 207 observed minima of 56 eclipsing binaries, 100 maxima of 21 RR Lyrae- and δ Cephei-stars, 82 results of 32 Mira stars and long period variables, and 47 results of 9 RV Tauri stars, semiregular, and irregular variables, from the years 1966 up to 1968.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV)

In this 11th compilation of BAV results of observations are given from the years 1973 till 1975 for 217 observed minima of 56 eclipsing binaries, 173 maxima of 25 RR Lyrae stars, 624 results of 89 Mira stars, 182 results of 47 RV Tauri stars and irregular variables, 52 results of 27 eruptive variable stars and 12 maxima of four δ Cephei stars.     

Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für veränderliche Sterne e. V. (BAV)

In this 9th compilation of BAV results of observations are given from the years 1969 up to 1971 for 208 observed minima of 46 eclipsing binaries, 72 maxima of 22 RR Lyrae- and δ-Cephei-stars, 232 results of 66 Mira stars, 72 results of 12 RV Tauri-stars and 22 results of 3 irregular variables and U Geminorum-stars.     

On the properties of very young massive infrared sources (Mitteilungen der Universitäts-Sternwarte zu Jena Nr. 169)

The data compiled for 34 very young massive compact infrared source (Becklin-Neugebauer objects) in a separately published catalogue serve as the basis for an investigation of their general properties. First, the correlations of the strength of the ice and silicate bands at 3.1 μm and 10 μm, resp., with each other and with other parameters of the sources are investigated. In accordance with theoretical expectations the strengths of both bands are not well correlated with each other. The ratio τ₁₀/τ₃ of their optical depths veries from 0.85 to 8 (and possibly up to 22). That implies for the number densities of the grains that (naked) silicate grains always are considerably more abundant than ice grains (grains with ice mantles). It follows from the discussion of the relationships between τ₁₀, the temperature parameter of the sources, and their luminosity that relations between τ₁₀ and temperature and possibly between τ₁₀ and the luminosity exist. Stellar wind models for the ionized region around the embedded star are favoured after the analysis of the intensities of the hydrogen infrred emission lines and the radio continuum. The limited observational data do not yet allow a decision on a correlation between the silicate band depth and energy content and/or the velocity of the bipolar outflow detected in a number of sources. The BN objects are clearly more frequently associated with H₂O masers than OH masers. The linear separations of the infrared peaks from the masers are compatible with models where the H₂O masers are situated near the edges the gas-dust shells of the BN objects.     

A Catalogue of Extremely Young,Massive and Compact Infrared Objects (Mitteilungen der Universitäts-Sternwarte zu Jena Nr. 165)

Starting from the Becklin-Neugebauer Object in Orion as a prototype, a class of compact infrared sources thought to be young massive stars surrounded by optically thick dust shells is identified by means of a wide range of their observable features. A catalogue of 34 such objects is compiled, providing comprehensive information such as infrared and radio spectra, maser sources, and outflow phenomena.