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1.
Two new equations of state obtained for matter constituting isothermal neutron star core by using isentropic nature of matter for the equalities =2 and =3 (where 's are usual adiabatic exponents) have been utilised to discuss the internal temperature of core. The temperature of matter has been obtained asT=T
a(P+E)/. Variation ofT/T
a(t) with energy density has been discussed for these new equations of state and some standard equations of state for nuclear matter. 相似文献
2.
By considering the relativistic expression for isothermal NS cores,T·e
/2 = constant, we have shown that some of the standard equations of state, when applied to NS cores, correspond to constancy of some adiabatic exponents. It has been shown that the equation of state,P=KE, corresponds to 1 = to 2 = 3 1 +K and the equation of state, dP/dE=K, corresponds to 3 1 +K. The conditions under which different equations of state represent isothermal cores have been obtained: For isothermal NS, the local temperatureT, can be expressed in terms of pressureP, energy densityE, and rest mass density . For example: (a)P =KE
:T = constant × (E/); (b)P=KE :T = constant × (P/); (c) dP/dE =K :T
K
; (d) = 2 :T = constant × (P/E); and (e) = 3 :T = constant × (P/)1/2. Equation of state corresponding to = 2 is obtained as:P=E/ln(K/E) and the equation corresponding to = 3 comes out as:E=P ln(K/P). Core-envelope models can be developed for these two cases. When core equation corresponding to = 2 or = 3 is used in the core, we can ensure the continuity of dP/dE at the core-envelope boundary, along with the continuity ofP, E, , and . The parameters of isothermal NS cores corresponding to the cases = 2 and = 3, have been obtained. The maximum mass of these NS cores comes out to be 2.7 . 相似文献
3.
We can define some adiabatic exponents for neutron star cores. The equality of and 3 leads to an equation of stateE=P ln(K/P) orP=K exp(–E/P). This equation has been solved alongwith equations for hydrostatic equilibrium for different physical conditions at the centre. The parameters of isothermal neutron star cores have been computed by taking surface densityE
a=2×1014 g cm–3. ForP
0=E
0 the maximum mass and radius of neutron star core are 3.25M
and 17.14 km, respectively. 相似文献
4.
A. V. Tikhonov 《Astrophysics》2002,45(1):79-87
This investigation indicates an ambiguity in interpreting the results of applying the apparatus of the correlation gamma function [(r) and *(r)] to analyze the spatial distribution of objects from some sample. The presence of a linear section in the dependences of log() on log(r) and of log(*) on log(r) proves to be insufficient to state that the distribution has fractal properties (self-similarity). It is shown that a change in the geometrical boundaries of the sample may influence the form of the dependences of log() on log(r) and of log(*) on log(r). 相似文献
5.
J. J. Aly 《Solar physics》1987,111(2):287-296
We consider a simple model in which the coronal magnetic field B is assumed to be potential in the region between the solar surface
o
and an exterior source-surface 1 of arbitrary shape. We prove that the boundary value problem that determines B from the value B
lof its component on
0 along either
(orthoradial direction) or
(fixed direction) has at most one solution. On the other hand, we show that a solution can exist only if B
lsatisfies some solubility conditions. 相似文献
6.
M. S. El-Nawawy 《Astrophysics and Space Science》1990,164(2):213-229
General forms of theB-p relation are investigated in both the isothermal and the non-isothermal regions. The magnetic flux dissipation either by ambipolar diffusion or by Ohmic dissipation has been studied. The rates of heating due to the magnetic dissipation processes have been calculated in comparison with the rate of compressional heating.The magnetic field strength is derived as a function of flux/mass ratio, mass, density, and geometry of the isothermal cloud. In the non-isothermal region, the temperature is added to the above-mentioned variables.It has been found that the magnetic flux starts to dissipate via ambipolar diffusion at neutral density ofn>3×109 cm–3. Ambipolar diffusion continues effective until reaching densities ofn>1011 cm–3, where Ohmic dissipation dominates. Under some conditions, the electrons evaporate from the grain surface atn>1013 cm–3, while the ions are still adsorbed on the grain surfce. In this case, the magnetic flux loss returns to be influenced by ambipolar diffusion.The rates of heating by both Ohmic dissipation
OD
and ambipolar diffusion
AD
are found to be smaller than the rate of compressional heating
C
in case of magnetic dissipation. Assuming that the magnetic field is frozen in the medium, then
C
is smaller than both
OD
and
AD
. The above results of heating were found in the non-isothermal region. 相似文献
7.
Multiple expansion of the tidal potential 总被引：1，自引：0，他引：1
F. Mignard 《Celestial Mechanics and Dynamical Astronomy》1978,18(3):287-294
The Earth tidal deformation causes an additional gravitational potential. Its effect on the Moon orbital motion has been studied by several authors.In this contribution, we develop this additional potential without specifying the inertial frame chosen.For this purpose, we use the properties of the representation of rotation groups in 3 dimensions space. We finally obtain the interaction potential between the distorted Earth and the Moon which is a necessary preliminary to the study of the evolution of the Earth-Moon system.Nomenclature T.R.O
Tide raising object
- (, , )
Spherical coordinates of the T.R.O.
- (J,
E
)
Earth spin axis orientation.
E
is the longitude of the ascending node of Earth's equator on thexy-plane
- (a
,I
,e
, , ,M
)
Elliptics elements of the T.R.O 相似文献
8.
An empirical method for determining line source functions, previously applied by us to the cores of infrared lines has now been extended to the whole line profile and was applied to centre-limb observations of sixteen lines of five infrared multiplets, mainly of high excitation potential (Table I). The present investigation was performed in two steps. In the first part of the paper approximate values are derived for the depth dependence of the four functions named in the title of this paper, where
L
is the ratio between the actual and the LTE population of the lower level of the transitions involved. In the second part of the paper we use these empirically derived functions to compute the line profiles. From the remaining differences between observed and computed profiles, corrections are derived to the four functions. The main results are: (a) Convective velocities: see Table IV.(b)(Micro-)turbulent velocities: see Figure 8. Between
5 = 10-4 and 10-1:
1.4 km s-1, which is an upper limit since an unknown contribution of macroscopic motions could not be separated, (c) Line source functions: see Figures 9, 15 and 16. The source functions are close to the black-body function for
5 10-3, slight deviations occur in higher levels. The interesting behaviour of the Caii source function near
5 = 10-5 should be noted. (d) Non LTE-functions: first approximations for the functions log
L
(
5) were derived empirically in the first part, and are shown in Figure 10; the second approximation shows them to be too large and the real values seem to be closer to one-half or one-third of these functions. 相似文献
9.
We report new properties of solar magnetic fields in a quiet region as found from their magnetic power spectra. The power spectra of network and intranetwork fields (non-network fields) are separately calculated from a Big Bear magnetogram obtained with moderately high spatial resolution of 1.5 arc sec and a high sensitivity reaching 2 Mx cm-2. The effect of seeing on the power spectrum has been corrected using Fried's (1966) Modulation Transfer Function with the seeing parameter determined in our previous analysis of the magnetogram. As a result, it is found that the two-dimensional power spectra of network and non-network fields appear in a form: (
1)
-1 and (
1)
-3.5. Here
0 0.47 Mm-1 for network fields and
0 0.69 Mm-1 for non-network fields, the latter of which corresponds to the size of mesogranulation;
1 3.0 Mm-1 for both, which is about the size of a large granule. The network field spectrum below
0 appears nearly flat, whereas that of non-network fields instead decreases towards lower wave numbers as (
)
1.3. The turnover behavior of magnetic field spectra around
1 coincides with that found for the velocity power spectrum, which may justify the kinetic approach taken in previous theoretical studies of the solar magnetic power spectra. 相似文献
10.
A limiting case of the problem of three bodies (m
0,m
1,m
2) is considered. The distance between the bodiesm
0 andm
1 is assumed to be much less than that between their barycenter and the bodym
2 so that one may use Hill's approximation for the potential of interaction between the bodiesm
1 andm
2. In the absence of resonant relations the potential, double-averaged by the mean longitudes ofm
1 andm
2, describes the secular evolution of the orbits in the first approximation of the perturbation theory.As Harrington has shown, this problem is integrable. In the present paper a qualitative investigation of the evolution of the orbits and comparison with the analogous case in the restricted problem are carried out.The set of initial data is found, for which a collision between the bodiesm
0 andm
1 takes place.The region of the parameters of the problem is determined, for which plane retrograde motion is unstable.In a special example the results of approximate analysis are compared with those of numerical integration of the exact equations of the three body problem.
m 0,m 1,m 2. , m 0 m 1. m 2, m 1 m 2 m 1 m 2 . , . . , m 0 m 1. , . .相似文献
11.
Wan, Wilson and Sen (1986) have examined the scope of Modified Spherical Harmonic Method in a plane medium scattering anisotropically. They have used the phase functionp(µ, µ) = 1 +aµµ. In this paper, the Transfer Equation has been solved by the Modified Spherical Harmonic Method using the phase functionp(µ, µ) = 1 +
1
P
1(µ)P
1(µ) +
2)P
2(µ)P
2(µ) and a few sets of numerical solution have been predicted for three different cases. 相似文献
12.
The properties of a sample of IR galaxies from the Point Source Catalog z (PSCz) Survey were investigated using the correlation gamma function [(r) and *(r)]. The results with different volume-limited subsamples indicate that the regions of strong correlations (a power-law decrease in density with distance with an exponent 1 1) are limited to a scale of 10-15 Mpc. A break is present at this scale in the dependences of log() on log(r) and of log(*) on log(r). Such a break is also observed for various other samples of galaxies and clusters (at different scales). After the break the density dependence changes to another regime, corresponding to a fully uniform distribution for bright galaxies in the northern Galactic hemisphere. For some subsamples of the southern and northern hemispheres the latter regime corresponds to some decrease in density with distance. Indications of significant differences between the distributions of objects in the southern and northern hemispheres are obtained. It is shown that the section of the gamma function after the break, even when its extent is small, is a significant indicator of actual correlation properties of the distributions. The results of the analysis are in good agreement, on the whole, with preceding studies of the PSCz survey. 相似文献
13.
V. I. Ferronsky S. A. Denisik S. V. Ferronsky 《Celestial Mechanics and Dynamical Astronomy》1979,19(2):173-201
It is found that the relationship between the potential energy and the moment of the inertia independent of the radial mass distribution obtained earlier for the sphere also holds in the case of the ellipsoidal mass distribution for the ellipsoid of rotation.The possibility of application of the energy virial relations for solution of the evolutionary problems of the gravitating gaseous sphere, with the help of the relationship found earlier, is demonstrated. The physical conditions on the gaseous sphere boundary are introduced. The existence of two branches of evolution, the proton one and the electron one, is established. The problem of the gravitational contraction velocity during sphere evolution is solved. The relationship between the boundary temperature and the gaseous sphere radius as well as between the luminosity and the body mass is obtained. Some limiting relations for the final stage of the gaseous sphere evolution are found.
, , , . . . — . . , . .相似文献
14.
We consider the possibility that gravitational energy may play a local as well as global role in the behavior of matter in strong gravitational fields. A particular idealized equation, suggested as representing uniform energy density in general relativity, is examined, and its stability with respect to oscillatory and convective perturbations shown to be consistent with general relativistic hydrodynamics, subject to a new physical effect predicted for the behavior of fluids moving in strong fields. We calculate from this idealized equation the mass of a non-rotating neutron star, obtaining a maximum surface redshift ofz=2.48 and a maximum core mass of 9.79
14
–1/2
M. This compares withz=2.00 and 11.4
14
–1/2
M for a Schwarzschild star (=const.) and 6.8
14
–1/2
M for a causal star (dP/d1). 相似文献
15.
Г. А. Гурзадян 《Astrophysics and Space Science》1977,46(2):471-484
, , , , ,S
, , , S
Mg. , . , . , ( , ..). B5 B0; (<1%). 相似文献
16.
V. Markellos C. Goudas G. Katsiaris G. Georgantopoulos 《Astrophysics and Space Science》1976,45(1):99-103
A generalization is expressed of the Poisson theorem referring to the invariance of the planetary semi-major axes using the restricted problem model. In particular, it is shown that first and second approximation in terms of a change in the initial states of planets describing closed motions in the solar system remain invariant in modulus after any number of revolutions. But third-order terms contain secular parts and, thus, they undergo a secular change in their orbital motion. Such change would be apparent after
-2 Jovian years, where is a constant and is the maximum initial deviation of each planet from its reference orbit. 相似文献
17.
G. A. Gurzadyan 《Astrophysics and Space Science》1981,80(1):211-230
It is shown that the observed color diagrams(U-B)
f
(B-V)
f
for pure flare emission of UV Cet type flare stars may be explained within the framework of a fast electron hypothesis. We point out the essential influence on these color indices of the two following factors: (a) the deviations of the normal radiation capability of the star in the infrared region of spectra (on 3.6 m, 4.4 m, and 5.5 m) from the Planckian distribution; (b) the location of the cloud (source) of fast electrons around the star (flare geometry effect). Under the real conditions of the generation of flares around the star the frequency transformation law at the photon-electron interaction has a view =n20, wheren may take the different values-from 0.15 up to 4; it depends on the cloud-star-observer geometry. By the observed colors of the flare emission may be understood, in principle, the location of flare source around the star. A possible role of reflection effect at the generation of stellar flares is outlined. 相似文献
18.
Г. Н. Дубошин 《Celestial Mechanics and Dynamical Astronomy》1970,2(4):454-466
(, 1969). ( ), ( ), , , . , (=), , , .. , . , , - ( ), ( ). , .
This paper is a continuation and a generalization of one published earlier (Duboshin, 1969): it discusses the problem whether there exist the Lagrangian and the Eulerian solutions of the generalized three-body (material points) problem. Every point in this generalized problem acts on another, one with a force (attractive or repulsive) directed along the straight line passing through these points, and in an arbitrary manner depending on time, mutual distance and its derivatives, the first and the second. Here, generally speaking, the third axiom of dynamics (law of action and reaction) is not presupposed as fulfilled, that is, it is supposed that every two material points interact in a different way.This most general assumption being made, we establish the conditions which must dictate the laws of the interactions, so that the three points can always remain at the apexes of the equilateral triangle (Langrangian solution), or remain always on a straight line (Eulerian solution).The author believes that such general treatment of the three-body problem can be useful for theoretical studies in celestial mechanics and also for practical applications in the study of isolated stellar systems.相似文献
19.
, . () . , , , . ( ), , , . . (2.7). ( 1 k
1 ,V — , — .) (k
1) (k) §2 ( (2.14)). , (3.6) (3.4), (3.8) . (3.9)–(3.13) ( (3.9), (3.10) (3.11) , (3.12)–(3.13) ). (3.14), (3.16)–(3.19). - . (3.15). ( (4.14)–(4.15)). (4.23)–(4.25). (4.26)–(4.28). §5. , . ((5.5)–(5.6)). , . (5.10) . 相似文献
20.
I I I : Mgas<0.04 Mcor. - . , . 相似文献