摘要:

AbstractAus Streifenzählungen an 20 offenen Sternhaufen werden die charakteristischen Parameter ihres Aufbaues abgeleitet. Das relative Potential beträgt am Haufenrand im Durchschnitt 0.32. Die von SCHWARZSCHILDeingeführte effektive Entfernung der Sterne vom Haufenmittelpunkt gleicht etwa dem Haufenradius. Die Zählungen an zwei Haufen erlauben es, deren kumulative Massenfunktionen bisMv ≈ 8 fortzusetzen und die sich anzeigende exponentielle Konvergenz zur Massenbestimmung zu verwenden. Dasselbe konnte für die Plejaden und sieben Haufen nach den ZählungenVAN DENBERGHSund SHERSgetan werden. Die mittleren Geschwindigkeiten und die mittleren UmlaufszeitenTder Haufensterne sind von der Ordnung 0.90 km/s bzw. 12 · 106Jahre. Zwischen letzteren und der mittleren (Massen‐) Dichte · gilt die BeziehungT≈≈ 20 · 106. In 1 · 109Jahren verliert der mittlere Haufen die Hälfte seiner Stern

ISSN:0004-6337    

DOI:10.1002/asna.19702920502

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractDie Verteilung der Wolken auf der Oberfläche des Planeten Mars in den Oppositionsjahren 1948, 1958, 1963, 1965 und 1967 wird graphisch dargestellt. Die Wolkenhäufigkeit pro Längengrad zeigt eine positive Korrelation mit der bei 21°.5 Nord gemessenen Radar

ISSN:0004-6337    

DOI:10.1002/asna.19702920503

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractThe change of the slope in the luminosity function of the members of the Coma cluster nearM≈ — 21 is interpreted as an evolutionary effect. Originally there should have existed many luminous objects now being evolved to invisible masses in form of “black holes”. If the faint part of the luminosity function is extrapolated beyondM≈ — 21 the observed discrepancy in the mass of the cluster determined by the virial theorem and by summing up the individual masses of the galaxies vanishes. The comparison of the hypothetical frequency of the black holes with the estimated numbers of the strong extragalactic radio sources encourages us to the assumption of a relation between the two groups

ISSN:0004-6337    

DOI:10.1002/asna.19702920504

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractThe paper is the first in a series dealing with the structure of magnetic and rotating neutron stars including general relativistic effects. The geometry of fossile magnetic fields frozen in the highly conductive neutron star matter in a non‐rotating (or weakly rotating) star is studied. § 2 treats the general poloidal field in a vacuum outside the star. The geometry of magnetic fields within the star — whose matter is governed by a barytropic equation of state — is restricted by the condition that the magnetic force density should be curl‐free to maintain equilibrium (§ 3). Numerical results are obtained for a poloidal and a toroidal dipole fi

ISSN:0004-6337    

DOI:10.1002/asna.19702920505

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractLichtelektrische UBV‐Beobachtungen des Veränderlichen SV Cephei zeigen quasiperiodische Minima wechselnder Tiefe und Gestalt, die nicht von Änderungen der Farbindizes begleitet sind. Zur Deutung des Lichtwechsels werden zirkumstellare Wolken aus meteoritischen Körpern von cm‐Größe vorgeschlagen, die das Sternlicht in statistischer Folge abschwächen. Die quantitative Diskussion zeigt, daß zur Erklärung der Beobachtungen einige 105Wolken mit einer Gesamtmasse von weniger als 1% der Sternmasse ben

ISSN:0004-6337    

DOI:10.1002/asna.19702920506

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractIn this paper the mathematical tools for future calculations of the diffuse radiation field inside a homogeneous spherically symmetric dust nebula are made available. The solution of the equation of radiative transfer is represented as an expansion after LEGENDREpolynomials. Making use of the operator calculus a system of ordinary differential equations is derived the solution of which yields the coefficients of this expansion. The method developped here is more general as well as more rigorous than previous work in this field.

ISSN:0004-6337    

DOI:10.1002/asna.19702920507

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractDie Koeffizienten der Farbgleichung für die am Tautenburger Schmidt‐Teleskop bestimmten Blau‐Helligkeiten zeigen eine Abhängigkeit von der Außentemperatur. Mögliche Ursachen dieses Effekts werden dis

ISSN:0004-6337    

DOI:10.1002/asna.19702920508

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractFor investigation of the inner structure of interstellar clouds with aid of the photographic photometry the dust density in the clouds must be higher than a minimum value depending on the diameter of the clouds and on the size of the structure elements to be recognized. There is also a highest value of the density for these observations depending on the extent of the clouds, on the spatial distribution of A‐type stars, and on the used observing instrument. The calculations were done for an instrument of about 24 inches aperture (Schmidt‐camera of the Jena Observatory).The smallest clouds, which can be investigated with an instrument of this aperture and reasonable demands of the size of structure elements, must have a diameter of 15 pc. The mean dust density of this cloud has to be about 4 · 10−25g cm−3. The density of bigger clouds can vary within a determined interval, e.g. 10−25g cm−3

ISSN:0004-6337    

DOI:10.1002/asna.19702920509

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractIn a region at α (1900) = 00h08mand δ (1900) = 60°.6 the dependence of the interstellar extinction on the distance was investigated with aid of photographic photometry in the UBV‐system. In a field of 1°.5×1°.5 the extinction was measured at one hundred points arranged in a square grid.Three clouds of interstellar dust with distances of 800 pc, 1000 pc, and 1100 pc were found. The investigation of the inner structure of the clouds was possible because many points are lying in the area of each cloud. A result is the increase of the density from the edges of the clouds to the cloud centres. The density gradient is increasing with decreasing diameters of the clouds.The central density seems to be in inverse proportion to the dimensions of the clouds. With the data of these three clouds and some observations of AMPELand IWANISZEWSKAa connection between the masses and the diameters was found. This relation differs a little from the same connection found by SCH

ISSN:0004-6337    

DOI:10.1002/asna.19702920510

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractThe behaviour of the masses, the luminosities, the radii, and the colours of the RR Lyrae stars situated in 7 globular, clusters is investigated in dependence upon the clusters' age. The ages were determined according to a method by SANDAGE; the determination of the masses is based on relations derived by BAKER.In is found that, with increasing age of the clusters, the mean values of masses, luminosities, and radii of the RR Lyrae variables decrease whereas the periods become larger and the centres of the RR Lyrae gaps bluer. The masses tend (with large scattering) to values smaller than one solar mass and support in this respect the models by CHRISTYand by FAULKNERand IBEN.

ISSN:0004-6337    

DOI:10.1002/asna.19702920511

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY