Bemerkungen zur Geschichte der Himmelsmechanik

Ohne ZusammenfassungPaper presented at the Conference on Celestial Mechanics, Oberwolfach, Germany, Aug. 17–23, 1969.     

Zur Metallhäufigkeit in offenen Sternhaufen

The noteworthy deviations and differences given in the individual values of the metal abundance of open clusters were studied. It could be shown that the metal abundance of open clusters, which are situated in or near the galactic plane (|z| ≦ 0.3 Kpc) are not only correlated wiht the galactocentric distance (RGC ) but also with the galactic longitude l of the clusters. This correlation is not given in the open clusters of high |z|-distances. There, the metal abundance is connected as well with the galactocentric radius (RGC ) as with the distances of the objects form the galactic plane.     

Bemerkung zur scheinbaren Entfernungsabhängigkeit der HUBBLE-Konstante

The apparent dependence of the HUBBLE constant on the distance observed by LE DENMAT et al. is obviously caused by the luminosity distribution of the ScI galaxies.     

Blaue Objekte in der Umgebung von M31 II. Häufigkeitsverteilung und Statistik

This paper presents a statistical investigation of 999 blue objects [U(–B) 0.00, limiting magnitude U = 20, B = 21], the majority of which is newly discovered on M31-plates (predominantly taken by F. Börngen ) of the large Schmidt telescope of the Karl Schwarzschild Observatory Tautenburg. A list of the objects is given elsewhere [G. A. RICHTER (1973)].For “very blue objects” [(U – B) -0.40] the number per square degree brighter than magnitude B is as follows: log N_B = 0.72 B -13.1 (starlike objects), log N_B = 0.63 B -12.0 (diffuse and probably diffuse objects). This confirms the results of other authors: log N_B increases more rapidly than in the case of constant density (0.6); there are about 10 QSOs brighter than B = 20 per square degree. A detailed discussion concerning the optical identification of discrete radio sources will soon be given.     

Zur Metallhäufigkeit in ω Centauri

Radiation pressure during the high-luminosity collapse phase of cluster evolution may, under certain circumstances, lead to the ejection of interstellar grains. For the most luminous clusters such ejection might produce significant depletion of heavy elements. It is suggested that the metal abundance dispersion that has recently been detected among the giant stars in ω Centauri (which is the brightest known galactic globular cluster) might be accounted for by such radiation pressure induced heavy element depletion.     

Eine neue Methode zur Bestimmung der statistischen Zählverluste bei Photonenzählern

A simple method for the determination of statistical pulse losses of photon counting photometer in dependence on the pulse intensity was deveoloped. The slowly decereasin brightness of the clear sky in the dusk serves a light source. With the help of neutral filter one gets two different pulse rates for two intensities. From a series of such measurements with different intensities one can derive the correction in dependence on pulse density in form of a power sequence.     

Eine einfache Methode zur Bestimmung und Berücksichtigung der Zählverluste bei Photonenzählern

The statistical puls loss by the use of a photon counting photometer can be corrected on the base of the equation n = Ne^−Nι. A simple method is given for determination of the parameter ι which can be realized on each photometer.     

Ein Programm zur Periodensuche bei großen Anzahlen von Meßwerten

A method for the search of periods in large series of observational data is discribed. Like that proposed by Lafler and Kinman our procedure is based on the computation of the variance, however, the speed of computation of periodogramms is considerably higher since we do not need to size the values with regard to the phase. A FORTRAN-programm is given.     

Singularitäten in der Allgemeinen Relativitätstheorie

“Regular solutions of EINSTEIN 's equations” mean very different things. In the case of the empty-space equations, R_ik = 0, such solutions must be metrics g_ik(x^l) without additionaly singular “field sources” (EINSTEIN 's “Particle problem”). – However the “phenomenological matter” is defined by the EINSTEIN equations R_ik – 1/2g_ikR =–xT_ik itselves. Therefore if 10 regular functions g_ik(x^l) are given (which the inequalities of LORENTZ -signature fulfil) then these g_ik define 10 functions T_ik(x^l) without singularities. But, the matter-tensor T_ik must fulfil the two inequalities T ≥ 0, T ≥ 1/2 T only and therefore the EINSTEIN -equations with “phenomenological matter” mean the two inequalities R ≥ 0, R ≤ 0 which are incompatible with a permanently regular metric with LORENTZ -signature, generally.     

Zur dynamischen Äquivalenz der post-NEWTONSCHEN Näherung für die Planetentheorie in der allgemeinen Relativitätstheorie und in der trägheitsfreien Mechanik mit RIEMANNSchem Gravitationspotential

Proof of the dynamical equivalence of the post-NEWTONian approximations for the LAGRANGAIN representations of planetary motions according to GRT and according to our “RIEMANNian dynamics with MACH EINSTEIN doctrine”. Finally, we discuss the equivalence problem for general post-NEWTONian LAGRANGians of the one-body Problem in celestical mechanics.     

Beobachtungsmöglichkeiten zur Linschen Dichtewellentheorie (Mitteilungen der Universitäts-Sternwarte zu Jena Nr. 130)

After summarizing the most important effects predicted by the density-wave theory the possibilities of observing these effects are discussed. The observation of structural effects in our own Galaxy is very difficult, mainly because of the inaccurate distances available. Only rough structures can be obtained. That is also true for observations near such points, in which the line of sight is tangential to the spiral arms. Observations of kinematical effects in our own Galaxy and of structural effects (kinematical ones are not discussed) in extragalactic spiral systems should yield some useful results.     

Verfahren zur Abgleichautomatisierung von Irisblendenpohotometern (Mitteilung der Universitäts-Sternwarte zu Jena Nr. 121)

Following a critical review of automatical output techniques of equality-information in iris-type photometers put into practice previously, in this paper new possibilities are discussed. One of these methods which is based on digital-techniques and is easy to realize resolves differences between the intensities of the comparison and measuring beam of less then 10⁻³.     

Empirische Atmosphärenmodelle zur Erklärung des Lichtwechsels magnetischer Sterne

Empirical model atmospheres on the basis of MIHALAS models were investigated. If the temperature of the outer layers in a spot is higher than in the surrounding normal atmosphere and lower than in the deeper layers, many characteristics of the observed amplitude-wavelength relation of magnetic stars can be explained.     

Koordinateninvariante Erhaltungssätze in der Schwarzschildgeometrie

Einstein's field equations can be written in a special way to give expressions free of any quantities which cannot be measured. These expressions are fully coordinate invariant but observer dependent. Generalized LORENTZ transformations according to TREDER 's theory serve as connecting links between the measured values of different observer systems. The field equations contain expressions for gravitational energy and stresses which satisfy covariant conservation laws.     

Der Mechanismus der dreimonatigen Oszillation des Großen Roten Flecks auf dem Jupiter

The present paper is a test to explain the three-month oscillation of the Great Red Spot on Jupiter as a solution of the NAVIER-STOKES equation which is coupled with a nonlinear equation of oscillation. Since several parameters resp. functions are unknown it is difficult to find quantitative solutions.     

Über schnelle Änderungen der magnetischen Feldstärke von Sonnenflecken

The results from hourly measurements of the magnetic field strengths of several main spots in three selected spot groups within the years 1968/69 are given in graphs. The values of the field strength used in the graphs are mean values out of three spectrograms taken immediately one after another. The mean error of a mean value is ±85 Gauss. Besides a general tendency in the daily course of the field strength the graphs are showing rapid variations up to 500 Gauss within a few hours. In contrast to these variations which are probably real, the frequent short time variations indicated cannot be regarded as certain. In addition to the observations of the field strength the development of the spot groups is described, and informations on the flare-activity are given.     

Über periodische Bahnen im eingeschränkten Dreikörperproblem und in der Nähe der Kommensurabilitäten vom Typus (k + 1)/k

The authors, collaborating during the winter 1966/67, performed numerical investigations on form and character of periodic solutions of the restricted problem of three bodies in the Sun–Jupiter-System and in the neighbourhood of the resonances of the (k + 1)/k type. The principal part of these computations which were achieved using a fast IBM-computer refers to the cases 2/1 (Hecuba-gap) and 3/2 (Hilda-group). The results gave new insight into the genealogy of periodic orbits in the regions which do not contain solutions of Poincaré's first genre. Moreover, L. Carpenter tried to develop an analytical theory (here not explicitely described) which leads to convergent trigonometric series for the coordinates of periodic orbits with restricted eccentricities, using the method of general perturbations in rectangular coordinates recently published by P. Musen and himself.     

Absolute Eigenbewegungen ausgewählter blauer Objekte in der Nähe des galaktischen Nordpols

Es werden absolute Eigenbewegungen von 74 blauen Objekten der Größenklassen 16_μ^m5 bis 19_μ^m5 und von weiteren 28 schwachen Sternen (17_μ^m5) in der Nähe des galaktischen Nordpols angegeben. Die absoluten Eigenbewegungen wurden in Bezug auf 45 Referenzgalaxien als Mittel aus 5 im B-System aufgenommenen Tautenburger Schmidt-Platten bestimmt. Die mittleren Fehler der Eigenbewegung für einen Stern betragen m̄ = 0_˝″0058 und m̄ = 0_˝″0069. Für ein blaues Objekt mit einer B-Helligkeit zwischen 17_m̄^m0 und 18_m̄^m0 erreichen diese Fehler die Werte m̄ = 0_˝″0059 und m̄ = 0_˝″0051, und sie vergrößern sich mit Abnahme der Helligkeit. Für 16 der untersuchten blauen Objekte konnte mit einer Wahrscheinlichkeit von 0.99 die Existenz von Eigenbewegungen nachgewiesen werden. The absolute proper motions of 74 blue objects (from 16_m̄^m5 up to 19_m̄^m5) and 28 additional faint stars (17_m̄^m5) near the galactic north pole are presented. They were derived with reference to 45 galaxies as the mean value from 5 plates taken in the B-system with the Tautenburg Schmidt telescope. The mean errors of the proper motion of a star are equal to m̄ = 0_˝″0058 and m̄ = 0_˝″0069. The errors of a blue object with a B-magnitude between 17_m̄^m0 and 18_m̄^m0 are m̄ = 0_˝″0059 and m̄ = 0_˝″0051 and increase with decreasing brightness. For 16 of the investigated blue objects it was possible to show that proper motions exist with a probability of 0.99.