ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oscillatory Model for Radio Source 3 C 273 (1964)
    [s.l.] : Nature Publishing Group
    Nature 201 (1964), S. 1016-1016 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Smith and Hoffleit4 have examined the luminosity history of the object and found that its brightness underwent rather drastic changes during the past eighty years. The light curve exhibits fluctuations of a time-scale of the order ten years, on which occasional light flashes are superimposed. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2011016a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Magnetoturbulent Energy and Stability of Supermassive Stars (1965)
    [s.l.] : Nature Publishing Group
    Nature 207 (1965), S. 1345-1346 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE discovery and subsequent investigation of the quasi-stellar radio objects, or 'quasars', have aroused great interest by many investigators1-5. The observed luminosities are of the order of 1046 ergs sec-1 and their lifetimes fall in the range of 103-106 years. Hoyle and Fowler6 proposed that a ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2071345a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Excitation of Lunar Luminescence by Solar Protons (1964)
    [s.l.] : Nature Publishing Group
    Nature 202 (1964), S. 1097-1098 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] After this discovery, Kopal and Rackham2'3 observed on the night of November 1.-2, 1963, twice a red glow in the Kepler region of the Moon. These observations were made through narrow passband interference niters centred at 6725 A in the red, and at 5450 A in the green. The red photographs showed a ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2021097a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The equilibrium and stability of magnetopolytropes (1969)
    Springer
    Astrophysics and space science 4 (1969), S. 255-274 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The theory of the oscillations of axisymmetric gaseous configurations with a prevalent magnetic field is presented. The virial tensor method is used to obtain the nine second harmonic modes of oscillations of the system. It is found that out of the nine modes, three are neutral, four are non-radial, and two are coupled. For the Prendergast spherical model it is found that one of the coupled modes is radial and the other non-radial. Both the radial and the non-radial modes obtained in this case agree with the corresponding formulae obtained byChandrasekhar andLimber (1954) andWoltjer (1962). The equilibrium structure of gaseous polytropes with toroidal magnetic fields is also investigated in detail for values of the polytropic indexn=1, 1.5, 2, 3 and 3.5. For this model the components of the moment of intertia and potential energy tensors together with the non-zero components of the supermatrix potential are obtained. The final results in terms of the effect of weak toroidal magnetic fields on the characteristic frequencies of distorted polytropes are presented in the form of tables.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00661818
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    On rotating isothermal configurations in the post-Newtonian approximation of general relativity (1973)
    Springer
    Astrophysics and space science 24 (1973), S. 117-126 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The equations which govern the structure of a rotating, truncated isothermal sphere in the post-Newtonian approximation of general relativity are derived and solved numerically. Each model is parameterized by both a rotation and a relativity parameter. The density inside the configurations is tabulated and graphed as a function of both distance from the center and co-latitude. Relativistic gravitational effects are found to pull the models into states which are considerably more centrally condensed than one predicts classically. Rotation tends to flatten the isothermal configurations into oblate spheroids, though for even the largest rotation parameters the degree of flattening is only a few percent. The computed models may be similar to the cores of relativistic star clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00648679
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The stability of supermassive stars in the Parametrized Post-Newtonian framework (1974)
    Springer
    Astrophysics and space science 31 (1974), S. 295-304 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The binding energy and stability of supermassive stars (SMS's) is examined in the framework of the Parametrized Post-Newtonian (PPN) formalism of Will and Nordvedt. The PPN formalism encompasses the post-Newtonian limit of virtually every theory of gravity, differentiating between theories by means of nine PPN parameters. A general expression is derived for the energy integral in the PPN framework, and it is found that only in those theories in which the parameters ζ1=ζ2=ζ3=ζ4=α3=0 will the energy be conserved. In all such theories, a SMS of radius less than a critical radius will be unstable against adiabatic radial perturbations. Present experimental limits on the PPN parameters γ and β do not exclude the possibility of the existence of stable, non-rotating, hydrogen-burning SMS's of masses an order of magnitude larger than the upper limit for the mass of such stars predicted in general relativity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00644088
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Nonlinear coupling between pulsation and convection in late type stars (1976)
    Springer
    Astrophysics and space science 45 (1976), S. 175-190 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A simple idealized nonlinear model applicable to long period variable stars has been formulated that assumes the convective envelope ofM giants is composed of giant convection cells, which are comparable in size to the stellar radius. The simplicity of this model essentially constitutes a physical analog to the strong dynamic coupling that occurs if the convective envelope of the star undergoes both modes of motion. As shown implicitly in the time scales associated with these motions, the coupling produces asymmetrical fluctuations of the entire star, the mean velocity of which is comparable to the escape velocity of the star at particular values of the ratio of the pulsation and convection time scales. It is suggested that this can account for the mass loss from late type stars, and the circumstellar dust shells that are associated extensively with long period variables. For critical values of the pulsation and convection time scales, the solutions correspond to the rapid expansion of the entire convective envelope, and is the basis of a new mechanism that simulates the manner in which pulsating stars ballistically accelerate their convective shells to form planetary nebulae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00642153
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    On non-adiabatic oscillations of gaseous systems in hydromagnetics (1973)
    Springer
    Astrophysics and space science 24 (1973), S. 105-115 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The general variational principle obtained by Unno for the study of stellar stability is extended to include the effects of magnetic fields in the general case where the perturbations are nonadiabatic. The unperturbed configuration is non-rotating, but internal motions are possible. A general stability equation is derived, using the modified variational principle. In the simplest case, this equation is identical to the one derived by Unno except for the appearance of magnetic terms in one of the coefficients (through the Lorentz force). If dissipation is neglected, the characteristic equation reduces to the one derived by Frieman and Rotenberg in the stationary case and by Kovetz in the static case. The stability of magnetic stars against homologous oscillations is examined and the usual result for the dynamical mode is obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00648678
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Heating of the solar chromosphere and corona (1976)
    Springer
    Astrophysics and space science 43 (1976), S. 187-197 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The generalized inhomogeneous wave equation that governs magnetoacoustic, vortical and thermal motions in compressible fluids and that thus is applicable to the problem of the heating of the solar chromosphere and corona is obtained. The effects of kinematic and bulk viscosity, heat conduction, Joule dissipation and magnetic diffusivity are included. Under the usual assumptions, the generalized wave equation reduces to the well-known equations of Lighthill, Kulsrud, Phillips and others. The major problems encountered in applying Lighthill's mechanism to sound generation in turbulent media are reviewed for both the subsonic and supersonic cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00640565
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Models of rapidly rotating white dwarfs (1968)
    Springer
    Astrophysics and space science 2 (1968), S. 520-528 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Numerical solutions of the structural equations for rapidly rotating white dwarfs are tabulated for values of the central density parametery −2 o ranging from 0.0001 to 0.80. The physical parameters of white dwarfs rotating at the break-up velocity are also tabulated. Further, the massradius relations for both the equatorial and the polar radii are derived. These two relations are found to differ from other recent theoretical calculations by less than 10 and 4%, respectively. The use of uniformly rotating white dwarf models to account for the observational data on Sirius B is discussed. It is concluded that Sirius B may be rotating rapidly and near its break-up velocity. Further it is suggested that the radius and Einstein red shift for this star are 0.01135 R⊙ and 59 km/sec.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02175927
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...