摘要:

AbstractA detailed reinvestigation of the Coma cluster basing on enlarged observational material of number density distributions and radial velocities of galaxies as well as radio and x‐ray data is performed and supports our previous conclusion that this cluster possesses a substructure. This substructure is in the south‐western region of the cluster and produces the impression of an elongated cluster structure in the direction of the bridge between Coma and A 1367. A 1656 seems to be a cD‐like cluster with NGC 4874 as the only dominating giant central g

ISSN:0004-6337    

DOI:10.1002/asna.2113110202

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113110204

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractFor the minimally coupled scalar field in Einstein's theory of gravitation we look for the space of solutions within the class of closed Friedmann universe models. We proveD≥ 1, whereD≥ is the dimension of the set of solutions which can be integrated up tot→ ∞ (D>0 was conjectured by PAGE(1984)). We discuss concepts like “the probability of the appearance of a sufficiently long inflationary phase” and argue that it is primarily a probability measure μ in the spaceVof solutions (and not in the space of initial conditions) which has to be applied. μ is naturally defined for Bianchi‐type I cosmological models becauseVis a compact cube. The problems with the closed Friedmann model (which led to controversial claims in the literature) will be shown to originate from the fact thatVhas a complicated non‐compact non‐Hausdorff Geroch topology: no natural definition of μ can be given.We conclude: the present state of our universe can be explained by models of the type discussed, but thereby the anthropic principle cannot b

ISSN:0004-6337    

DOI:10.1002/asna.2113110205

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113110207

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe diffusion of scalar fields (temperature, density number of some admixture) in a compressible medium showing an isotropic, homogeneous and stationary turbulence is considered. The derived formulae for turbulent diffusivity χT(ξ) hold up to ξ ≈ 1, where ξ =u0τ0/R0(u0, τ0, andR0are characteristic velocity, life‐time, and correlation length of turbulent pulsations, respectively. The velocity field of turbulent motionsu(r, t) is assumed to be known and the influence of the scalar field ontou(r, t) is neglected. It is shown that the velocity correlators, which change their signs in dependence on the space corrdinates, may give negative values for ξT(ξ)

ISSN:0004-6337    

DOI:10.1002/asna.2113110208

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe position angle and separation of 320 double stars from Pourteau's Catalogue (18h<α<19h) measured on the prints of the Palomar Observatory Sky Survey 50 years after their discovery are given

ISSN:0004-6337    

DOI:10.1002/asna.2113110209

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113110210

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractEs wird eine Übersicht über die im Jahr 1988 auf Tautenburger Schmidtplatten gefundenen Kleinen Planeten gegeben. 386 Objekte wurden entdeckt und für diese 1218 Positionen gerechnet. Es handelt sich um 87 numerierte Objekte sowie um 299 Planetoiden mit provisorischer Bezeichnung. Unter letzteren sind 252 neue Bezeichnungen. Für 40 im Berichtszeitraum numerierte Planeten haben Tautenburger Beobachtungen einen Beitrag geleistet. Darunter sind acht in Tautenburg entdeckte Planetoi

ISSN:0004-6337    

DOI:10.1002/asna.2113110211

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113110213

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe many discoveries of main belt asteroids with insufficient observations for reliable orbits cause special difficulties for identifications and data storage; mainly because of the mixing of objects due to their motion in α and δ. This problem may be reduced by substituting positions by slowly and smoothly varying quantities. A rational system of preliminary designations will be proposed, and surveys and compact ephemerides are discussed. All computations are very simple and performed on a small, programmable pocket compute

ISSN:0004-6337    

DOI:10.1002/asna.2113110214

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY