A white and a red star     

Cornelis De Jager 《Solar physics》1996,169(2):443-464

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Torsion and inflation     

Venzo De Sabbata  C. Sivaram 《Astrophysics and Space Science》1991,176(1):141-144

We show that considering the torsion in early universe, we are led to an inflationary expansion with only a massless scalar field, so avoiding all physical questions that we are facing when working with massive scalar field.  相似文献   

A new investigation on neutralino dark matter: relic density and detection rates     

A. Bottino  V. De Alfaro  N. Fornengo  G. Mignola  S. Scopel 《Astroparticle Physics》1992,1(1)

The main properties of the neutralino dark matter are revisited in the light of the new theoretical developments in Susy theories and of the recent constraints from accelerators and underground experiments. The neutralino relic abundance and the detection rates relevant for direct and indirect searches are evaluated in the minimal supersymmetric standard model (MSSM) with the full inclusion of the (one-loop) radiative corrections, both to the Higgs masses and to the trilinear Higgs self-coupling. The relevance of these corrections for the neutralino-neutralino annihilation cross-section, and thus for the relic density, is discussed in detail. Large regions of the parameter space are considered, including those where the neutralino only provides a fraction of the local dark matter density; in these domains the standard value for the local density is appropriately scaled down. Some general properties of the detection rates as functions of the MSSM parameters are also elucidated; in particular it is shown that in the regions of the parameter space where scaling of the local density occurs, the rates are largely independent of two of the model free parameters. The relevance of the Kamiokande upper bounds to the upgoing muon fluxes is discussed in connection with the possible neutrino outputs from the Earth and from the Sun due to neutralino accumulation and annihilation in these macroscopic bodies. Finally, the complementarity between the search for neutralino dark matter and the discovery potential of future accelerators is discussed.  相似文献   

Bounds for mass and rotation of black holes in the observable universe     

A. De Vries  R. Böhme  Th. Schmidt-Kaler 《Astrophysics and Space Science》1995,225(2):221-226

The bounds for the energy change rate of a Maxwell field in the outer space of a rotating black hole, calculated by de Vries (1994) and de Vries (1995), enable us to deduce limits for the rotation and the mass of black holes. For this purpose we assume that a certain part of the anisotropies of the cosmic background radiation is due to absorption or superradiance of black holes (Teukolsky, 1973, Starobinskii and Churilov, 1973). The knowledge of these anisotropies yields bounds for rotation and mass of the black holes in the observable universe.  相似文献   

The dielectric analogue of magnetohydrodynamics     

Bibhas R. De 《Astrophysics and Space Science》1988,144(1-2):99-104

Almost half a century after Alfvén first conceived of the science of magnetohydrodynamics, it is still possible to trace his intuitive thinking to explore physical processes heretofore not considered. The ideas of magnetohydrodynamics (applicable to conducting fluids) can be transferred almost intact to purely dielectric fluids, such that we can arrive at a generalized concept applicable toany fluid-conducting or dielectric. In this sense, Alfvén's conception of magnetohydrodynamics may be ideationally even more profound than it has been thought to be so far.Paper dedicated to Professor Hannes Alfvén on the occasion of his 80th birthday, 30 May 1988.  相似文献   

Anelastic Rayleigh Wave Attenuation In the Iberian Peninsula   总被引：1，自引：0，他引：1  

Jose A. Canas  Fernando De  Miguel†  Francisco Vidal†  Gerardo Alguacil† 《Geophysical Journal International》1988,95(2):391-396

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A Variable Slip Fault Model For the 1908 Messina Straits (Italy) Earthquake, By Inversion of Levelling Data   总被引：1，自引：0，他引：1  

Giuseppe De  Natale Folco Pingue 《Geophysical Journal International》1991,104(1):73-84

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Modelling and distance determination of planetary nebulae     

P. A. M. Van Hoof  G. C. Van De Steene 《Astrophysics and Space Science》1995,224(1-2):579-580

At present the lack of a good, generally accepted distance scale is the major limitation in the study of Planetary Nebula (PN) evolution and their distribution. We describe our fully self-consistent method to derive the physical parameters of a PN, including its distance, from a set of observables. For this we calculate various models and search for a best fit of the model predictions to the observables. An accurate determination of the angular diameter is important for a good distance determination. We think that we shall achieve an accuracy of 30% in distance. We estimate the error in stellar temperature at less than 15% and the uncertainty in the abundances at 0.10 dex.  相似文献   

The Millennium Galaxy Catalogue: on the natural subdivision of galaxies     

S. C. Ellis  S. P. Driver  P. D. Allen  J. Liske  J. Bland-Hawthorn  R. De Propris 《Monthly notices of the Royal Astronomical Society》2005,363(4):1257-1271

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Models of the millimeter-centimeter spectra of the giant planets     

Imke De Pater  Steven T. Massie 《Icarus》1985,62(1):143-171

Hitherto Jupiter's spectrum at short millimeter wavelenghts showed a clear discrepancy with model calculations (e.g., G.L. Berge and S. Gulkis, 1976, In Jupiter (T. Gehrels, Ed.), pp. 621–692. Univ. of Arizona Press, Tucson). A similar although less pronounced, discrepancy appears to exist for Uranus and Neptune. One explanation of this discrepancy is that additional absorbers not included in the model calculations are present in the atmosphere. It was suggested that uncertainties in the absorption coefficient of ammonia, especially at millimeter wavelengths, may be responsible for at least part of the discrepancy. A comparison of various model atmosphere calculations with data for all four giant planets is shown. The absorption profile of ammonia at centimeter wavelengths was assumed to be rightly represented by a Ben Reuven line profile, which enabled the derivation of information on the vertical distribution of ammonia in these planets' atmospheres. It appeared that ammonia must be depleted in the upper atmospheres of all four planets by a factor of 4–5 with respect to the solar abundance for Jupiter (and Saturn) and by a factor of 100–200 for Uranus and Neptune. At deeper layers the optical depth is larger, due either to a larger abundance of ammonia or to absorption by the presence of water. Given the vertical ammonia distribution in the atmospheres as derived from the centimeter data, a best fit to the millimeter spectra of all four planets was found by changing the high frequency tail of the ammonium lineshape profile. This, we feel, is legitimate since the profile at millimeter wavelenghts is not or is only poorly known due to the absence of laboratory spectra for ammonia as a trace constituent in an otherwise hydrogen gas. It was found that a line profile which at millimeter wavelenghts more closely resembles a Van Vleck-Weisskopf lineshape than the usually adopted Ben Reuven profile gives a rather satisfactory fit to the data of all four gaseous planets.  相似文献