bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computation of sCHWARZSCHILD's periodic solutions in the restricted three‐body problem
Authors: Leimanis Eugene , Olund Brian R. 
Published: July 2007

AbstractPeriodic solutions may be characterized by the mean values and initial values of their orbital elements. Accordingly in Chapter I a method is developed for calculating the mean values and in Chapter II a method is given for calculating the initial values of the orbital elements in the case of SCHWARZSCHILD's periodic solutions. The methods are illustrated by numerical calculations for the commensurabilities 2:1, 3:1, 3:2, and 5:3 of the mean motions of the planetoid and Jupiter.
The Effect of Interstellar Medium Parameters on the Accretion by Neutron Stars
Authors: Amnuel P. R. , Guseinov O. H. 
Published: July 2007

AbstractThe effect of the magnetic field trapped into the interstellar gas on the accretion by neutron stars is considered. The account of the magnetic field decreases the accretion by 2 orders.As a result of accretion the luminosity of the neutron stars is found to be ∼ 1028 – 1029 erg/s and so their observation as X‐ray sources is hardly probable.
On the post‐NEWTONian approximation of theories of gravity
Authors: Kasper U. , Liebscher D.‐E. 
Published: July 2007

AbstractThe physical meaning of the parameters of the post‐NEWTONian approximation is considered from a theoretical point of view. It is shown that the post‐NEWTONian approximation of any LORENTZ‐covariant theory, which implies POISSON equations for every metric coefficient in the linear approximation, is the member of a three‐parametric family of post‐NEWTONian metrics. Some tetrad theories are cited.
On the REYNOLDS stresses in mean‐field hydrodynamics III. Two‐dimensional turbulence and the problem of differential rotation
Authors: Rüdiger G. 
Published: July 2007

AbstractIt is well‐known that, in a rotating star, a meridional circulation directed from pole to equator contributes a latitude dependence to the law of rotation, as it is observed on the Sun. It is also known that such a circulation is produced by a radial dependence of the original angular velocity if the outer parts of the convective zone possess a higher angular velocity than the inner parts. In this paper it is shown that a two‐dimensional turbulence with velocity vectors perpendicular to the radial direction, necessarily leads to the required relation dω0/dr > 0. This also holds when there is an additional three‐dimensional homogeneous and isotropic turbulent field. The characteristic lengths of the two turbulences would, however, have to have different orders of magnitude whenever the horizontal turbulence should not be strictly two‐dimensional but posses correlation lengths finite in all directions. The application of this to explaining also the phenomenon of the superrotation of the Earth's upper atmosphere is suggested. In the final chapter the possibility of the occurrence of negative viscosity on the Sun is discussed.
NEWTONsche Relativ‐Mechanik
Authors: Treder H.‐J. 
Published: July 2007

AbstractNEWTONs Mechanik impliziert die dynamische Absolutheit der Bewegungen, welche zum Auftreten absoluter Beschleunigungen in den Bewegungsgleichungen führt. Gegen NEWTON haben HUYGENS (und nach ihm z. T. LEIBNIZ und KANT sowie später MACH und POINCARÉ) gefordert, daß in die Dynamik eines abgeschlossenen Systems von n Teilchen Pa nur relative kinematische und dynamische Größen, nämlich die Differenzen der zu den Teilchen gehörenden absoluten Größen, eingehen dürften. — Es wird gezeigt, daß für ein im D'ALEM‐BERTSchen Sinne abgeschlossenes Partikel‐System, das entsprechend der atomistischen Hypothese von HERTZ aus N Teilchen derselben Masse m besteht, eine reine Relativ‐Mechanik genau dann formulierbar ist, wenn dieses System im Ruhsystem seines Schwerpunktes dargestellt wird. HAMILTON‐Funktion und LAGRANGE‐Funktion usw. enthalten dann nur Relativ‐Größen im Sinne von HUYGENS, KANT und POINCARÉ. — Die absolute Natur der Beschleunigungen in der NEWTONschen Mechanik zeigt sich hier jedoch in einer dynamischen Paradoxie, die sich dann ergibt, wenn zwei nicht miteinander wechselwirkende Partikel‐Systeme gedanklich zu einem System zusammengefaßt werden. Diese Paradoxie verschwindet bei einer genuinen Modifikation der NEWTONschen Dynamik im Sinne des MACHschen Prinzips der Relativität der Trägheit.
Response of Rigid Rotators to Gravitational Radiation
Authors: Dautcourt G. 
Published: July 2007

AbstractDie Reaktion eines axialsymmetrischen starren Rotators auf einfallende Gravitationsstrahlung wird für bestimmte Zustände der freien Bewegung des Rotators mit Hilfe der EULERschen Gleichungen für Wellenlängen diskutiert, die groß gegenüber den Dimensionen des Rotators sind. Erstens tritt unter dem Einfluß senkrecht zur Rotationsachse einfallender Strahlung geeigneter Polarisation eine kleine Abweichung auf, wenn Rotations‐ und Symmetrieachse ursprünglich zusammenfallen. Zweitens ändert sich die Winkelgeschwindigkeit einer senkrecht zur Symmetrieachse erfolgenden Rotationsbewegung in einem sich in Richtung der Rotationsachse ausbreitenden Wellenfeld um einen kleinen Betrag (BRAGINSKI‐Rotator.)Für monochromatische Resonanzstrahlung mit Wellenfrequenzen gleich der Rotationsfrequenz (im ersten Fall) oder gleich der doppelten Rotationsfrequenz (im zweiten Fall) ist die Wirkung auf den Rotator groß genug, um für künftige Experimente von Interesse zu sein.
Les composantes du déplacement séculaire du pôle d'inertie de la Terre
Authors: Fichera Elio , Pugliano Antonio 
Published: July 2007

AbstractNach Homogenisierung des Deklinationssystems des ILS‐Katalogs wird die säkulare Bewegung des mittleren Poles untersucht. Unsere Analyse führt zu zwei Komponenten dieser Bewegung: Einer bereits bekannten fortschreitenden Komponente und einer elliptischen.
Frozen Scintillation Caused by Low‐Frequency Gravitational Radiation
Authors: Dautcourt G. 
Published: July 2007

AbstractIntensive kosmische Gravitationsstrahlung im Megaparsek‐Wellenlängenband verursacht neben anderen Effekten eine kleine Winkelverschiebung entfernter Strahlungsquellen. Es wird eine kurze Behandlung des Effektes gegeben.
General Remarks on the Variability of Spotted Stars
Authors: Friedemann C. , GÜRtler J. 
Published: July 2007

AbstractDer Lichtwechsel, der als Folge eines dunklen Fleckes in der Photosphäre eines Sternes auftritt, wird untersucht. Die Gestalt der Lichtkurve hängt von der Lage des Fleckes auf der Sternoberfläche, der Orientierung der Rotationsachse des Sternes bezüglich des Beobachters, der Größe des Fleckes und der Temperaturdifferenz zwischen Fleck und Photosphäre ab. Die Flecken führen zu einer Verschiebung des Sternes im Farben‐Helligkeits‐Diagramm.
Photometrische Kalibrierung von Schmidtspiegelaufnahmen durch ein bildteilendes Hilfsprisma
Authors: Bronkalla W. , Notni P. , Wempe J. , BÖRNGEN F. , Ziener R. 
Published: July 2007

AbstractLichtteilerprismen können zur Kalibrierung von Platten des Tautenburger Schmidtspiegels nur verwendet werden, wenn die Aufnahmen schraffiert werden. Fokale Sternbildchen zeigen stark störende Auswirkungen der im Haupt‐ und Nebenstrahlengang unterschiedlichen Bildstruktur‐, Szintillations‐ und Intermittenzverhältnisse.
The Number‐diameter Relation of Galaxies
Authors: Richter G. M. 
Published: July 2007

AbstractContrary to the number‐magnitude relation, the number‐angular diameter relation is influenced by the luminosity function. The number‐diameter counts by DODD et al. (1975) are in agreement with the normal luminosity function and a homogeneous space distribution without a local density excess. Almost all the faint small (<18 arcsec) galaxies may be first‐ranked cluster members.
Radio spectra of some markarian galaxies
Authors: Dickinson D. F. , Kojoyan G. , Purton C. R. , Sramek R. A. , Tovmassian H. M. 
Published: July 2007

AbstractRadio spectra of 16 Markarian galaxies are studied between 2.7 and 15.5 GHz. The Seyfert‐type galaxies have power‐law spectra with an average spectral index of ‐0.82, except for MRK 348, which is an active galaxy with a complex spectrum. The galaxies with featureless optical spectra have rather flat radio spectra, similar to BL Lac‐type objects.
Über die Möglichkeit, die Temperaturverteilung in Sonnenflecken durch einen anisotropen Wärmetransport zu erklären
Authors: Eschrich K.‐O. , Krause F. 
Published: July 2007

AbstractAuf der Grundlage der numerischen Lösungen eines Wärmeleitungsproblems in einem anisotropen Medium werden Möglichkeiten erörtert, die Verteilung der Temperatur in Sonnenflecken und deren Umgebung zu erklären. Als Grund der Anisotropie wird das in Sonnenflecken und in dem Gebiet unterhalb derselben vorhandene starke Magnetfeld angesehen, das der Konvektion eine anisotrope Struktur (zweidimensionale Turbulenz) und damit im Mittel diesem Gebiet anisotrope Leitungseigenschaften aufprägt.Die Diskussion zeigt, daß die beobachtete Temperaturverteilung erklärt werden kann, falls das Gebiet, in dem Anisotropie vorliegt, eine Tiefe besitzt, die etwa so groß wie der Durchmesser oder größer ist.
Can redshift discrepancies in galaxy systems be explained by low‐frequency gravitational radiation? I. distant clusters
Authors: Dautcourt G. 
Published: July 2007

AbstractSome proposals have been made in recent years that extremely low‐frequency cosmic gravitational radiation with wavelengths of the order megaparsecs and larger and with the cosmological energy density may be able to explain the virial mass discrepancy in at least some systems of galaxies. The question is rediscussed here with the result that — for all conceivable spectral densities — the gravitational wave influence on the propagation of light from a galaxy cluster does not solve redshift problem for rich and distant clusters — at least if waves with an energy density not exceeding the critical cosmological density are considered.
The influence of direct solar radiation pressure on the nodal period of artificial earth satellites
Authors: Mioc V. , Radu E. 
Published: July 2007

AbstractApproximate formulae for the evaluation of the effect of direct solar radiation pressure (neglecting the POYNTING‐ROBERTSON effect and shadow effect) on the nodal period of artificial Earth satellites with quasi‐circular orbits are derived. The cases of osculating elements considered in the ascending node and of circular orbits are studied.
Beobachtungsergebnisse der Berliner Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV)
Authors: Braune W. , Hübscher J. , Mundry E. 
Published: July 2007

AbstractIn dieser 11. Zusammenstellung von Beobachtungsergebnissen der BAV werden 217 beobachtete Minima von 56 Bedeckungssternen, 173 Maxima von 25 RR Lyrae‐Sternen, 624 Ergebnisse von 89 Mira‐Sternen, 182 Ergebnisse von 47 RV Tauri‐ und unregelmäßigen Sternen, 52 Ergebnisse von 27 eruptiven Veränderlichen und 12 Maxima von vier δ Cephei‐Sternen der Jahre 1973 bis 1975 mitgeteilt.
The equidensitometric determination of angular diameters of compact galaxies
Authors: Richter N. , Högner W. 
Published: July 2007

AbstractOn Tautenburg Schmidt plates in system V taken at seeings of about 2″ the determination of real angular diameters of compact galaxies down to 4″ is possible. Diameter‐magnitude diagrams of objects in four fields around the globular cluster M3 show the possibility for getting homogeneous material concerning both the uniformity of the equidensitometric copying process and the measuring process with the iris photometer in order to determine the integral brightness of single galaxies from their limiting equidensities.
Spectroscopic investigations of the magnetic Ap star HD 9996
Authors: Scholz G. 
Published: July 2007

AbstractSpectroscopic measurements of the Ap star HD 9996 yielded the radial velocity and the strength of the effective magnetic field. From the reversal of the magnetic field periods smaller than 4.92 years can be excluded. We cannot state an exact period, but a value of 20.60 years seems to be the most probable one. Further we find hints at a short period of about 1.8 days for the variations in the radial velocities as well as in the magnetic field strengths. The elements of the binary motion were derived.
The x‐ray luminosity function of galaxy clusters
Authors: Schmidt K.‐H. 
Published: July 2007

AbstractFrom published data on X‐ray sources identified with clusters of galaxies the X‐ray luminosity function of the clusters was derived to ϕx ˜ Lx‐0.8 in the range 1043 ≦ Lx ≦ (2–3) · 1045 ergs/s. For Lx > 3 · 1045 ergs/s the function decreases abruptly.
The binary nature of the Ap star 53 Cam
Authors: Scholz G. 
Published: July 2007

AbstractThe radial velocities of the Ap star 53 Cam = HD 65339 show a longtime variation corresponding to a binary motion. For the elements of the binary system the following values were derived: K = 8km/s, γ = ‐2.2 km/s, P = 2380 days. e = 0.56, ω = 10°, and a · sin i = 22 · 107 km. A second period of about 1850 days is indicated but this value seems to be a spurious period.Investigations of ZEEMAN spectrograms made by several authors gave a magnetic period of a bout 8 days. This period, interpreted as rotational period of the star, obviously differs a little for various observational times depending on the position in the binary orbit; so that the period is smaller at the time of the apastron passage. At present it is not possible to decide wheter this behaviour – if real – preponderantly reflects changes of the velocity of rotation or of the magnetic field. Furthermore the radial velocities show a dependence on the state of ionization of the elements in such a way that evidently lines from neutral elements have larger radial velocities (absolute values) than those of the ionized elements. These differences also depend on the position in the binary orbit as mentioned for the magnetic periods.
The nonlinear dynamo problem: Small oscillatory solutions in a strongly simplified model
Authors: Bräuer H. 
Published: July 2007

AbstractFor a dynamo model obtained by idealizing features of the Sun, an analytic proof of the existence and a recursion formula for the determination of small time periodic solutions in a finite vicinity of the critical dynamo numbers are given. The nonlinear problem is solved by transforming the boundary value problem of the induction equation into a fixed point problem in an infinite dimensional sequence space and then applying the LYAPUNOV‐SCHMIDTmethod to reduce it to a relationship between dynamo number, amplitude and frequency.
On singularities in electrodynamics and gravitational theory
Authors: Von Borzeszkowski H.‐H. , Treder H.‐J. , Yourgrau W. 
Published: July 2007

AbstractThe singularity and particle problems in electrodynamics and gravitational theory are discussed. Comparing different modifications of MAXWELL's electrodynamics and general theory of relativity, arguments are given which show possibilities of solving these problems by a modification that replaces EINSTEIN's equations by those of the EINSTEIN‐BACH‐WEYL‐type.
Koordinatenverbesserungen von FK4‐Sternen aus Beobachtungen am Ni2‐Astrolab
Authors: Gerstbach G. 
Published: July 2007

AbstractAus einer größeren Anzahl astro‐geodätischer Lotabweichungsmessungen werden individuelle Koordinatenverbesserungen von 241 FK4‐Sternen abgeleitet. Sie betragen im Mittel 0″.2, mit Extrema von 0″.6. Die Hälfte der Werte stützt sich auf mindestens 8 Beobachtungen und besitzt trotz des einfachen Instrumentariums Genauigkeiten um ±0″.13. Vergleichende Untersuchungen zeigen, daß die Ergebnisse von systematischen Einflüssen frei und ihre mittleren Fehler zuverlässig sind.
A Catalogue of Galaxies within 10 MPC
Authors: Kraan‐Korteweg R. C. , Tammann G. A. 
Published: July 2007

AbstractA catalogue is given of the 179 known galaxies within 10 Mpc. The inclusion of a galaxy depends on its redshift (v0 ≤ 500 km s−1) or, in the case of 7 dwarf galaxies, on the fact that their distances are known to be small. The catalogue contains in addition 52 more distant galaxies with v0 ≤ 500 km s−1: 50 are bona fide Virgo cluster members and 2 are members of the Leo group. Positions, types, absorption‐corrected luminosities, and velocities are given for the catalogue galaxies. The catalogue is believed to be nearly complete for galaxies brighter than ∽ – 18m.5, but it contains also many considerably fainter galaxies. The galaxies within 10 Mpc form the Local Group with 28 members and seven additional groups with a total of 92 known members. 59 galaxies (33%) do not seem to belong to any group.
Secular Post‐NEWTONian Effects for the Restricted Three‐Body Problem in TREDER'S Dynamics with Induced Inertia
Authors: Fuchs H. 
Published: July 2007

AbstractIn the framework of TREDER'S dynamics, in which according to the MACH‐EINSTEIN‐doctrin the inertial masses are induced by the gravitational interaction with the particles of the cosmos, we calculate the secular post‐NEWTONian effects for the restricted three‐body problem. The dominant secular post‐NEWTONian variation of nodes and apsides is shown to be the same as in EINSTEIN'S theory of gravitation. The formulation of the gravodynamics in the HERTZian configuration space allows – as in General Relativity – the explanation of the effect as an “geodetic precession” of the lines of nodes and apsides.
Photographic UBV surface photometry and gross structure of the halo of M 82
Authors: Bronkalla W. , Notni P. , Tiersch H. 
Published: July 2007

AbstractWe present a surface photometry of M 82 of medium spatial resolution. Special attention was paid to good systematic photometric accuracy. The results are discussed in terms of the distribution of intensity, colour, reddening free parameteer Q and colour excess b‐V.The bright elongated body of the galaxy consists of a moderately old stellar population (1 – 3 · 109a) and is only slightly reddned with the exception of the central absorption lane and the southern central region. The chaotic fan‐like disturbance south of the center shows the colours of a very young (106 – 107a) highly reddened group of stars; according to polarimetric data from the literature we see their light scattered by dust.The population index Q of the inner halo is bluer than that of the disc everywhere (with the possible exception of the extreme western part). Two sources must be responsible for the illumination of the halo; one of them is responsible for the light from the great disturbances near the minor axis. Both may be located near center but must be partly shadowed. A major contribution of the disc to the illumination is less probable because the population index is different in most places of the halo from that of the disc.In addition to the dusty halo, obscuring dust is probably located to the south of the galaxy. This can be interpreted as part of a thick disc of dust embedding the stellar disc or as beeing connected to a proposed strip of B stars at the southern boundary of the visible disc. Both these interpretations lead to opposite results concerning the direction of the inclination of the disc. The inclination itself is estimated to lie between 80° and 90°.
EINSTEINund die Probleme der Optik1)
Authors: Frank I. M. 
Published: July 2007

AbstractEs wird zunächst ein Überblick über die frühen Publikationen der EINSTEINschen Arbeiten in Zusammenhang mit der Entwicklung der theoretischen Physik in der UdSSR gegeben. Ausführlich wird auf die Frage der Überlichtgeschwindigkeit sowie der Probleme des Dopplereffekts und des Wawilow‐Tscherenkow‐Effekts eingegangen. Spätere Ergebnisse werden den Arbeiten EINSTEINSgegenübergestellt. Die enge Beziehung zu den EINSTEINschen Arbeiten bereits aufgezeigten Konsequenzen wird dargestellt.
The Difference between the Nodal and Keplerian Periods of Artificial Satellites as an Effect of Atmospheric Drag
Authors: Mioc Vasile 
Published: July 2007

AbstractAn analytical expression for the difference caused by the atmospheric drag between the nodal and keplerian periods of artificial satellites with quasi‐circular orbits, moving in a spherically symmetrical atmosphere, is given. Some corresponding equations found by different authors are obtained as particular cases of the given equation.
On the flowers‐ruderman instability mechanism
Authors: Roberts P. H. 
Published: July 2007

AbstractFlowers und Ruderman untersuchten im Zusammenhang mit Neutronensternen das Stabilitätsverhalten von Konfigurationen, bei denen die magnetischen Feldlinien aus einem elektrisch leitenden Medium, in dem hydrostatisches Gleichgewicht herrscht, in umgebendes Vakuum austreten und wieder zurückgehen. Sie gewannen den Eindruck, daß eine solche Konfiguration instabil gegenüber Verrückungen ist, bei denen die magnetische Energie des äußeren Feldes erniedrigt wird, ohne daß in gleicher Weise die magnetische Energie und die innere Energie innerhalb des leitenden Bereiches erhöht werden. Die genannten Autoren diskutierten ebenfalls, wie die Wachstumsraten der Instabilitäten reduziert werden könnten, wenn – wie im Fall der Neutronensterne – das elektrisch leitende Medium von einem festen Mantel mit endlicher elektrischer Leitfähigkeit begrenzt wird. Diese Vorstellungen von Flowers und Ruderman werden hier anhand einfacher Beispiele illustriert.
Observations of Minor Plaets at Dresden Lohrmann Observatory
Authors: Asenjo E. , Böhme D. 
Published: July 2007

AbstractIn den Jahren 1979 und 1980 am Zeiss‐Sonnefeld‐Astrographen 300/1500 des Lohrmann‐Observatoriums in Dresden‐Gönnsdorf beobachtete Positionen kleiner Planeten werden mitgeteilt.
On Turbulent Heat Transport in Rotating Convective Zones
Authors: Rüdiger G. 
Published: July 2007

AbstractThis paper analyses the tensorial aspect of heat conduction which certainly becomes important for gravitationally stratified and rotating turbulent media. The structure of the eddy conductivity tensor is indeed a non‐trivial one for turbulences with correlation times not too short in comparison with the rotation period. Since this situation may be realized in the solar convection zone, a more complex formulation of solar heat‐flux problems is required rather than that with a scalar heat conductivity. We still neglect here all other energy transporters, i.e. radiation and meridional circulation, and treat a solar heat‐flux problem with a heuristic mean‐field ansatz of the eddy conductivity tensor. Its rotationally created latitude dependence always leads to a pole‐equator surface temperature difference, which proves to be negligibly small, however, if realistic assumptions for the outward decrease of density and correlation time are involved. As a final rough estimation shows, this screening effect of the outer radiating surface should work for all late‐type stars of the main sequence hence a “differential temperature” (in analogy to “differential rotation”) should not be expected for those stars.
Distances of Galaxies from the Apparent Size Distribution of Dark Clouds. II NGC 224, NGC 2841 and NGC 7331
Authors: Osman A.M.I. , Ella M.S. , Issa I.A. 
Published: July 2007

AbstractThe distances of three Sb galaxies NGC 224, NGC 2841 and NGC 7331 have been determined using the apparent size distribution of dark interstellar clouds in each of them. The distances of NGC 224, NGC 2841, NGC 7331 were found to be 727.7 ± 63 kpc, 8.07 ± 0.16 Mpc and 7.22 ± 0.15 Mpc, respectively.