共查询到20条相似文献，搜索用时 31 毫秒
1.
V. I. Ferronsky S. A. Denisik S. V. Ferronsky 《Celestial Mechanics and Dynamical Astronomy》1978,18(2):113-140
A relationship between the potential energy and the moment of the inertia for celestial bodies is heuristically discovered. This relationship consists in the constancy of the product of formfactors for the potential energy and the moment of the inertia. The product is independent of the body mass and its radial mass distribution.We find the exact solution of Jacobi's virial equation for a gravitating spherical body based on the relationship obtained. This solution represents the unharmonic radial oscillations of the body. The solution is valid for a wide class of celestial bodies including variable stars and relativistic objects for which a relativistic analog of Jacob's equation is derived.The period of the radial oscillations of the planets is estimated with the help of the solution found. We note the coincidence of the experimental data and our theoretical calculations for the Sun.We show the important role of the Coulomb forces in the formation of the planets. It is demonstrated that the Coulomb forces result in the relation between the planet masses and their average molecular weight. 相似文献
2.
The stability of 12 small dark globules has been analyzed by using the full scalar virial theorem without magnetic field. We have applied the virial theorem to 18 sub-condensations identified from the column density maps of 12 globules. The sub-condensations are approximated by a uniform sphere of equivalent mass for simplicity. Based on the conventional simplified version of virial theorem, where the viral mass is compared with the LTE mass, we can only say that almost all the sub-condensations are approximately in a virial equilibrium. When we apply the full scalar virial theorem, where the sum of all the energy terms does not vanish and the time variation of the moment of inertia should be kept, one third of our sample cores are likely to collapse, one sixth of them are expected to expand, and the rest half of them are in a dense phase of an oscillatory equilibrium. The globules in the diffuse phase of the oscillatory equilibrium may not be detected by conventional means, because they are too rarefied to get CO molecules excited or to shield molecules from UV photons, or because they may not withstand the tidal disruption by neighboring clouds. 相似文献
3.
4.
A method for determining the velocity field parameters free from the distortions due to the systematic variations of stellar parallaxes over the celestial sphere is proposed. The method is based on the approximation of parallaxes as a function of coordinates on the sphere using spherical harmonics and can be applied in those cases where the solar motion cannot be eliminated from the stellar proper motions. Numerical experiments have shown that our method is able to obtain accurate coordinates of the solar apex and to calculate the kinematic parameters of the Ogorodnikov-Milne model to within three coefficients of the decomposition of parallaxes into first-order spherical harmonics. Examples of applying the method to the stellar proper motions of the Hipparcos catalogue, which admits checking the results using trigonometric parallaxes, are provided. Such a check has been found to yield a positive result only for nearby stars at heliocentric distances that do not exceed 400 pc and for which the parallaxes were determined with a relative error of at least 30%. An interesting feature of this method is the possibility to construct the shape of the figure which is formed by the deviations of the parallaxes from the sphere corresponding to the average parallaxes of the stars under consideration. It should be specially emphasized that all of this is done in the complete absence of information about the stellar parallaxes. The “solar terms” of the stellar proper motions that are formed by the products of the parallaxes by the solar motion components relative to the centroid of stars are the main source of information about the parallaxes here. 相似文献
5.
The motion of a particle about a non-rotating 2nd degree and order-gravity field is investigated. Averaging conditions are applied to the particle motion and a qualitative analysis which reveals the general character of motion in this system is given. It is shown that the orbit plane will either be stationary or precess about the body's axis of minimum or maximum moment of inertia. It is also shown that the secular equations for this system can be integrated in terms of trigonometric, hyperbolic or elliptic functions. The explicit solutions are derived in all cases of interest.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
6.
R. Vanclooster 《Planetary and Space Science》1977,25(8):765-771
In the present paper the effect of a sinusoidal modulation of an electromagnetic field on the invariance of the magnetic moment is studied. Such a generalized invariant plays an important role in problems concerning the motion of charged particles in the non-uniform magnetic field of the magnetosphere or the solar wind. In order to find an adiabatic invariant J, a canonical transformation is introduced, and J is expanded in an asymptotic series in the relative modulation amplitude. We are studying the first and second order terms of this expansion. It is further shown that the curves J = constant closely fit the results obtained by a numerical integration of the system of differential equations governing the motion of the particles. 相似文献
7.
Rachad M. Shoucri 《Celestial Mechanics and Dynamical Astronomy》1996,65(4):373-388
Equations describing planar motion along a constant elliptical orbit in non-central force field are derived in a simple way and discussed. The angular moment along the elliptical orbit is not a constant of motion. The problem appears to be related to the problem of planar motion with drag force. Relations with related works are discussed. In presence of drag force, conditions for the force field to be derived from the gradient of a function are discussed, and -elation of this function with the potential function is indicated. 相似文献
8.
9.
A. E. Rosenbush 《Astrophysics》1999,42(2):140-148
The separation of novae into groups, proposed in Part 1 of this paper, is discussed: it is based on the criterion of the shape
of the light curve, plotted on “outburst amplitude-logarithm of shell radius ” scales. The observational characteristics of
novae belonging to certain groups are considered. Novae of the GQ Mus group may be characterized by x ray emission. The proposed
separation of novae into groups may be related to the structure of the shell ejected in the outburst. Novae with smooth light
curves have ellipsoidal shells without pronounced nonuniformities. Novae with temporary fading or with brightness fluctuations
in the transitional stage of the outburst have ellipsoidal shells with a nonuniform distribution of matter (equatorial and
tropical belts in novae of the DQ Her group, an equatorial belt for the RR Pic group, and a patchy structure for the CP Pup
group). Relationships among certain parameters of novae are considered: absolute stellar magnitude, outburst amplitude, shell
expansion velocity, etc. From the “depth of temporary fading in the transitional stage of the outburst-shell expansion velocity”
dependence it can be concluded that the kinetic energy of the shell may be a constant for novae of the DQ Her group.
Translated from Astrofizika, Vol. 42, No. 2, pp. 189–202, April–June, 1999. 相似文献
10.
David Vasak Johannes Kirsch Armin van de Venn Vladimir Denk Jürgen Struckmeier 《Astronomische Nachrichten》2024,345(2-3):e230154
This short paper gives a brief overview of the manifestly covariant canonical gauge gravity (CCGG) that is rooted in the De Donder-Weyl Hamiltonian formulation of relativistic field theories, and the proven methodology of the canonical transformation theory. That framework derives, from a few basic physical and mathematical assumptions, equations describing generic matter and gravity dynamics with the spin connection emerging as a Yang Mills-type gauge field. While the interaction of any matter field with spacetime is fixed just by the transformation property of that field, a concrete gravity ansatz is introduced by the choice of the free (kinetic) gravity Hamiltonian. The key elements of this approach are discussed and its implications for particle dynamics and cosmology are presented. New insights: Anomalous Pauli coupling of spinors to curvature and torsion of spacetime, spacetime with (A)dS ground state, inertia, torsion and geometrical vacuum energy, Zero-energy balance of the Universe leading to a vanishing cosmological constant and torsional dark energy. 相似文献
11.
V. I. Ferronsky S. A. Denisik S. V. Ferronsky 《Celestial Mechanics and Dynamical Astronomy》1981,23(3):243-267
The Hamiltonian form of Jacobi's virial equation, which permits obtaining solution of the equation while considering both gravitational and Coulomb interactions, is given for the system of the material points constituting a celestial body.On the basis of the numerical solutions, in the framework of the plasma model of a celestial body, it is shown that for the Coulomb interactions of charged particles the product of the form-factors and , entering expressions for the potential energy and the moment of inertia, remains constant.Without any model restrictions this conclusion is confirmed in case of the asymptotic time limit of simultaneous collision of all the charged particles of the system.A relationship between the potential energy of a spherically symmetrical celestial body and its mass through a phenomenological parameter, which is the sound velocity, is found from the consideration of the hydrostatic equilibrium condition of the body, taking the Coulomb interactions into account. 相似文献
12.
P. B. Jones 《Astrophysics and Space Science》1975,33(1):215-230
The magnetic distortion is estimated for neutron stars in which the matter in the interior consists of superfluid neutrons and superconducting protons. For type II proton superconductivity, the arrangement of magnetic flux in a two-dimensional lattice of quantized fluxoids and the kinetic energy of the supercurrent carriers cause some components of the spatially averaged stress tensor for field and superconductor to be several orders of magnitude greater than the components of the Max-well stress tensor for a uniform distribution of the same magnetic flux. It is shown that for the Crab pulsar PSR 0531+21, which is considered to have the greater part of its mass in the form of superfluid neutrons and superconducting protons, the magnetic distortion is almost certainly more important than the clastic energy of the outer shell in determining the departure of the inertia tensor from its spherically symmetric form. With the assumption that internal and external magnetic fields have the same symmetry axis, the external field dipole moment of the Crab pulsar is predicted to be approximately perpendicular to the spin direction, in agreement with a number of published interpretations of observational data. 相似文献
13.
Mass, radius and moment of inertia are direct probes of compositions and Equation of State (EoS) of dense matter in neutron star interior. These are computed for novel phases of dense matter involving hyperons and antikaon condensate and their observable consequences are discussed in this article. Furthermore, the relationship between moment of inertia and quadrupole moment is also explored. 相似文献
14.
Marcello Romano 《Celestial Mechanics and Dynamical Astronomy》2008,100(3):181-189
The exact analytic solution is introduced for the rotational motion of a rigid body having three equal principal moments of
inertia and subjected to an external torque vector which is constant for an observer fixed with the body, and to arbitrary
initial angular velocity. In the paper a parametrization of the rotation by three complex numbers is used. In particular,
the rows of the rotation matrix are seen as elements of the unit sphere and projected, by stereographic projection, onto points
on the complex plane. In this representation, the kinematic differential equation reduces to an equation of Riccati type,
which is solved through appropriate choices of substitutions, thereby yielding an analytic solution in terms of confluent
hypergeometric functions. The rotation matrix is recovered from the three complex rotation variables by inverse stereographic
map. The results of a numerical experiment confirming the exactness of the analytic solution are reported. The newly found
analytic solution is valid for any motion time length and rotation amplitude. The present paper adds a further element to
the small set of special cases for which an exact solution of the rotational motion of a rigid body exists. 相似文献
15.
《Chinese Astronomy and Astrophysics》2007,31(2):192-204
Under the post-Newtonian approximation, the internal and external metrics of a rigidly rotating oblate spheroid filled by a uniform and incompressible perfect fluid are obtained. And the analytic solutions of post-Newtonian metric components are derived by using the series expansion in an ellipsoidal coordinate system. For this specific problem, there are only finite terms remaining in the series expansion, so the obtained results can be used to study particle motion under these metrics. 相似文献
16.
E. Schmutzer 《Astronomische Nachrichten》2005,326(8):760-772
In this treatise the well‐known 2‐body problem with a rotating central body is systematically reinvestigated on the basis of the Projective Unified Field Theory (PUFT) under the following aspects (including the special case of the Newton mechanics): First, equation of motion with abstract additional terms being appropriate for the interpretation of the various effects under discussion: tidal friction effect as well as non‐tidal effects (e.g. rebound effect as temporal variation of the moment of inertia of the rotating body, general‐relativistic Lense‐Thirring effect, new scalaric effects of cosmological origin, being an outcome of the scalarity phenomenon of matter (PUFT). Second, numerical evaluation of the theory. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
17.
K. Saaidi H. Sheikhahmadi T. Golanbari S. W. Rabiei 《Astrophysics and Space Science》2013,348(1):233-240
We study the holographic dark energy (HDE) model in generalized Brans-Dicke scenario with a non-minimal coupling between the scalar field and matter Lagrangian namely Chameleon Brans Dicke (CBD) mechanism. In this study we consider the interacting and non-interacting cases for two different cutoffs. The physical quantities of the model such as, equation of state (EoS) parameter, deceleration parameter and the evolution equation of dimensionless parameter of dark energy are obtained. We shall show that this model can describe the dynamical evolution of fraction parameter of dark energy in all epochs. Also we find the EoS parameter can cross the phantom divide line by suitable choices of parameters without any mines kinetic energy term. 相似文献
18.
P. A. Tarakanov 《Astrophysics》1999,42(2):163-168
The fractal dimensionality of the distribution of gamma-ray bursts over the celestial sphere has been investigated. Current
data from the BATSE experiment were used. A value of D2 ≈ 2 is obtained, corresponding to a uniform spatial distribution of burst sources.
Translated from Astrofizika, Vol. 42, No. 2, pp. 219–224, April–June, 1999 相似文献
19.
James B. Hartle 《Astrophysics and Space Science》1973,24(2):385-405
Equations are given which determine the moment of inertia of a rotating relativistic fluid star to second order in the angular
velocity with no other approximation being made. The equations also determine the moment of inertia of matter located between
surfaces of constant density in a rotationally distorted star; for example, the moments of inertia of the crust and core of
a rotationally distorted neutron star can be calculated in this way. The method is applied ton=3/2 relativistic polytropes and to neutron star models constructed from the Baym-Bethe-Pethick-Sutherland-Pandharipande equation
of state.
Supported in part by the National Science Foundation.
Alfred P. Sloan Research Fellow. 相似文献
20.
A. N. Baushev 《Monthly notices of the Royal Astronomical Society》2009,398(2):783-789
We discuss the possibility of observing the products of the dark matter annihilation that was going on in the early Universe. Of all the particles that could be generated by this process, we consider only photons, as they are both uncharged and easily detectable. The younger the Universe was, the higher the dark matter concentration n and the annihilation rate (proportional to n 2 ) were. However, the emission from the very early Universe cannot reach us because of the opacity. The main part of the signal was generated at the moment the Universe had just become transparent for the photons produced by the annihilation. Thus, the dark matter annihilation in the early Universe should have created a sort of relic emission. We obtain its flux and the spectrum.
If weakly interacting massive particles (WIMPs) constitute dark matter, it is shown that we may expect an extragalactic gamma-ray signal in the energy range 0.5–20 MeV with a maximum near 8 MeV. We show that an experimentally observed excess in the gamma-ray background at 0.5–20 MeV could be created by the relic signal from the annihilation of WIMPs only if the dark matter structures in the Universe had appeared before the Universe became transparent for the annihilation products ( z ≃ 300) . We discuss in more detail physical conditions whereby this interpretation could be possible. 相似文献
If weakly interacting massive particles (WIMPs) constitute dark matter, it is shown that we may expect an extragalactic gamma-ray signal in the energy range 0.5–20 MeV with a maximum near 8 MeV. We show that an experimentally observed excess in the gamma-ray background at 0.5–20 MeV could be created by the relic signal from the annihilation of WIMPs only if the dark matter structures in the Universe had appeared before the Universe became transparent for the annihilation products ( z ≃ 300) . We discuss in more detail physical conditions whereby this interpretation could be possible. 相似文献