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1.
Since there are reasons for expecting supersymmetry in an underlying quantum theory of gravity, one is led to study quantum and classical cosmology with supergravity. In particular, classical solutions corresponding to these models could also be used to generate the quantization of supersymmetric minisuperspaces. In generating these solutions, the solution to the Rarita-Schwinger field in the cosmological background is also obtained. In this paper the supercosmological equations of Einstein-Rarita-Schwinger are solved for the micro-superspace sector of the Taub model, under the assumption =11*22 and
. The solution for the parameters of the metric and are proportional to each other in each order, the zeroth-order and also the second-order terms. The zeroth-order terms correspond to the solution in general relativity and are logarithmic in time, the 12 terms have an hyperbolic time-dependence. The Rarita-Schwinger field has the form cos((2/D
3)ln |t–t
0|) and oscillates an infinite number of times astt
0. This oscillating behaviour of the solution for is not only present when spinor fields are treated in a curved background, but also some cosmological wave functions behave in this manner. This solution is at the same time the supercosmological solution for the microsuperspace sector of the Taub model and also the Rarita-Schwinger field in this background.This work was supported in part by CONACYT grant P228CCOX891723, and DGICSA SEP grant C90-03-0347. 相似文献
2.
We develop an automatic, computer controlled procedure to select and to analyze the Network Bright Points (NBPs) on solar images. These have been obtained at the Sac Peak Vacuum Tower Telescope by means of the Universal Birefringent Filter and Zeiss H filters, tuned, respectively, along the profiles of the H, Mg-b1, Na-D2, and H lines.A structure is identified as an NBP if at the wavelength H- 1.5 A its maximum intensity is greater than I + 3 and its area is greater than 1.5 arc sec2 at I + 1.5, where I is the mean value and the standard deviation of the intensity distribution on the image. Each detected NBP is then searched and confirmed in all the remaining 31 images at different wavelengths.For each NBP several parameters are measured (position, area, mean and maximum contrast, Dopplergram velocity, compactness, and so on) and some identification constraints are applied.The statistical analysis of the various parameter distributions, for NBPs present within an active region and its surroundings, shows that two types of NBPs can be identified according to the value of their mean contrast C
min the H- 1.5 Å image (C
m 0.1 type I, C
m> 0.1 type II). The type I NBPs (all occurring on the boundaries of the supergranular network) appear to be much more frequent (180/26) than the type II ones.The size A of type I NBPs is less than 1.0 arc sec for H/H wings but of the order of 1.2 arc sec for Na-D2 and Mg-bl. The mean contrast C
m is around the value of 10% along the Na-D2 and Mg-bl profiles and of 20% along the H/H wings.The C
m - A scatter diagrams show, for the photospheric radiation (h < 100 km), a narrow range of variability for C
min correspondence with a wide range for A. For radiation orginated at higher levels (h > 200 km), the C
m- A scatter diagrams seem to indicate, even if with a large variance, that the highest C
m's tend to correspond to the highest A values.The mean Doppler shift is close to zero for Na-D2 and Mg-bl lines but negative (downward motion) for H and H lines.The type II NBPs tends to be preferentially located in the neighbourhood of small, compact sunspots and their detectability is almost constant through all the 4 studied line profiles. No conclusions can be derived on the mean size, contrast and Doppler shift values because their distributions are too dispersed. The only positive information is that its C
m- A scatter diagram, in H and H wings, indicates a wide range of variability for C
m in correspondence with very narrow range of variability for A. 相似文献
3.
With the help of a model atmosphere of the Sun we evaluate the pole-equator difference in flux (as measured by Dicke and Goldenberg) assuming the following type of pole-equator temperature difference (T=T
e
–T
p
): (a) T 2K for > 0 (0 0.05); (b) T 10K for < 0.The small T at all optical depths given by (a) could, for example, be due to a pole-equator difference in effective temperatures. At small optical depths a difference in mechanical heating could give rise to the larger temperature difference given by (b). We compare the results of our calculations with Dicke and Goldenberg's observations.The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
4.
We consider the problem of the influence of electron scattering on the continuous spectrum of an envelope. For the radiation flux out of the envelope we assume an expression (1) obtained by us previously [3]. Computations using formula (1) are carried out for two models of the envelope: gray andpurely hydrogen. As a result we find the values of the following quantities, which characterize the continuous spectrum: the color indices U-B, B-V, V-R, and V-I; the Balmer jump D, and the bolometric correction BC. The values of these quantities are given in tables as functions of the surface temperature To of the envelope and the parameter /, where is the coefficient of electron scattering and is the mean absorption coefficient. We draw conclusions on the role of electron scattering for each model of the envelope.Translated fromAstrofizika, Vol. 37, No. 3, 1994. 相似文献
5.
The effect of small perturbations and in the coriolis and the centrifugal forces respectively on the stability of the triangular points in the restricted problem of three bodies with variable mass has been studied. It is found that the range of stability of triangular points increases or decreases depending upon whether the perturbation point (, ) lies in one or the other of the two parts in which the (, ) plane is divided by the line J8–J9=0 where J8 and J9 depend upon , the constant due to the variation in mass governed by Jeans' law. 相似文献
6.
А. Л. Куницын 《Celestial Mechanics and Dynamical Astronomy》1971,3(2):222-226
. . . , , m
1, m2, m3, n ( .
The conditions of stability of the constant libration solutions of the general three-bodies problem obtained by E. Routh through investigation of the linearized perturbed motion equations are analised. To the values of the masses of the three bodies which satisfy boundary conditions of the region of stability the locus of all corresponding centers of masses is laid down in accordance with. It occurs that this locus is a circle, its centre coinciding with the geometric centre of the trianglem 1, m2, m3 and its radius being a function of exponent in the law of attraction of the bodies. The motion may be stable only if the centre of masses of the bodies lies outside the circle mentioned above. In the case of the Newtonian law of attraction the radius of this circle equals 0,943 |rmax| where |rmax| is a distance of the vertex from the centre of the trianglem 1, m2, m3. Thus stability is possible (if it is generally possible) inside a very small region in this case.相似文献
7.
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
8.
, . 2.7°- . . . E3×1019 (1.6) . 相似文献
9.
Infinite series expansions are obtained for the doubly averaged effects of the Moon and Sun on a high altitude Earth satellite, and the results used to interpret numerically integrated examples. New in this paper are: (1) both sublunar and translunar satellites are considered; (2) analytic expansions include all powers in the satellite and perturbing body semi-major axes; (3) the fact that retrograde orbits have more benign eccentricity behavior than direct orbits should be exploited for high altitude satellite systems; and (4) near circular orbits can be maintained with small expenditures of fuel in the face of an exponential driving force one forI
ab, whereI
b=180°–I
a andI
a is somewhat less than 39.2° for sublunar orbits and somewhat greater than 39.2° for translunar orbits.Nomenclature
a
semi-major axis
-
A
lk
coefficient defined in Equation (11)
-
B
lk
coefficient defined in Equation (24)
-
C
km
coefficient defined in Equation (25)
-
D, E, F
coefficients in Equations (38), (39)
-
e
eccentricity
-
H
k
expression defined in Equation (34)
-
expression defined in Equation (35)
-
I
inclination of satellite orbit on lunar (or solar) ring plane
-
J
2
coefficient of second harmonic of Earth's gravitational potential (1082.637×10–6
R
E
2
)
-
K
k, Lk, Mk
expressions in Section 4
-
expressions in Section 4
-
p=a(1–e
2)
semi-latus rectum
-
P
l
Legendre polynomial of degreel
-
q
argument of Legendre polynomial
-
radial distance of satellite
-
R
E
Earth equatorial radius (6378.16 km)
-
R, S, W
perturbing accelerations in the radial, tangential and orbit normal directions
- syn
synchronous orbit radius (42 164.2 km=6.6107R
E)
-
t
time
-
T
satellite orbital period
-
T
orbital period of perturbing body (Moon)
-
T
e
period of long periodic oscillations ine for |I|<I
a
-
T
s
synodic period
-
U
gravitational potential of lunar (or solar) ring
-
x, y, z
Cartesian coordinates of a satellite with (x, y) being the ring plane
-
coefficient defined in Equation (20)
-
average change in orbital element over one orbit (=a, e, I, , )
- 1,23
unit vectors in thex, y, z coordinate directions
-
r
,
s
,
w
unit vectors in the radial, tangential and orbit normal directions
- =+
angle along the orbital plane from the ascending node on the ring plane to the true position of the satellite
-
angle around the ring
-
gravitational constant times mass of Earth (3.986 013×105 km s–2)
-
gravitational constant times mass of Moon (or Sun)
-
m
gravitational constant times mass of Moon (/81.301)
-
s
gravitational constant time mass of Sun (332 946 )
-
ratio of the circumference of a circle to its diameter
-
radius of lunar (or solar) ring
-
m
radius of lunar ring (60.2665R
E)
-
s
radius of solar ring (23455R
E)
-
true anomaly
-
argument of perigee
- 0
initial value of
-
i
critical value of in quadranti(i=1, 2, 3, 4)
-
longitude of ascending node on ring plane
This work was sponsored by the Department of the Air Force. 相似文献
10.
The basic physical picture of the Algol system is reviewed, and, using collected red and infrared observations, photometric curve fits are investigated by applying numerical quadratures to determine theoretical light curves appropriate to Roche model stars. The contact nature of Algol B appears to be confirmed, and effective temperatures of the three components areT
A=11 400°,T
B=5300°,T
C=7600°. In terms of a Lambert's law approach to the reflection effect, the effective heat-albedo is required to be reduced from unity to one half; and it is also found that the averaged gravity-darkening coefficient is close to a value appropriate for a diffusion type of heat-transfer mechanism operating in sub-photospheric layers. 相似文献
11.
L. K. Babadzanjanz 《Celestial Mechanics and Dynamical Astronomy》1979,20(1):43-57
The method of obtaining the estimates of the maximalt-interval (
–,
+) on which the solution of theN-body problem exists and which is such that some fixed mutual distance (e. g.
12) exceeds some fixed non-negative lower bound, for allt contained in (
–,
+), is considered. For given masses and initial data, the increasing sequences of the numbers
k
, each of which provides the estimate
+ >
k
, are constructed. It appears that if
+ = +, then
. 相似文献
12.
A model of a first generation intermediate star of 5M
, with Z=0 has been considered. The model is at an advanced stage of its evolution and has a double shell burning. It burns helium in the inner shell, and hydrogen, via CNO cycle, in the outer shell.
=(log/log)
T
and
T
=(log/logT)
were computed allowing for the oscillations of the relative mass abundance of the reagents in nuclear reactions. Including
=(log/log)
T
and
=(log/logT)
of mean molecular weight and the effect of the oscillations of abundances due to nuclear reactions, stability was studied. Contrary to the results of the static calculations, we found that instability due to the excitation mechanism provided by the high temperature sensitivity of energy generation rate propagates up to the surface. Thus the model in question was found to be unstable against radial adiabatic pulsations, in its fundamental mode. 相似文献
13.
V. A. Ruban 《Astrophysics and Space Science》1977,46(2):L23-L28
It is shown that, for the scalar-tensor cosmology (STC) by Jordan-Brans-Dicke (JBD), in general anisotropic solution the oscillatory mixmaster regime near the singularity will be destroyed by the scalar source-free field and replaced by monotonousV
3-collapse into the point or into the line and plane (only in caseG0) even in the presence of the primordial source-free electromagnetic (EM) field. 相似文献
14.
In the framework of non-linear fluid theory we use a lower hybrid (LH) wave of the form
as a pump which interacts with the small fluctuations with the low-frequency vibrations
i
or =0, where
i
, is the hydrogen ion-cyclotron (HIC) gyrofrequency. The ponderomotive force generated by the beating of the high-frequency pump wave 0 and the sideband LH waves (±0) produces a non-linear coupling between the high- and low-frequency motions of electrons and ions. Under certain conditions the HIC waves and the zero-frequency waves both become parametrically unstable and start to grow. These excited waves then heat the ions by stochastic acceleration in the transverse direction, thus explaining the formation of ion comics along the auroral field lines. Electrons would be heated in the parallel direction directly by the pump field as well as by low-frequency waves. Thus a single mechanism can explain the existence of ion-cyclotron waves, zero-frequency waves, ion conics, and energetic electrons along the auroral field lines. 相似文献
15.
The thermal contrast , and the umbra-penumbraA
u/A
p, were calculated for 63 sunspots of various sizes and morphologies. Contrary to the assumptions of the PSI model, andA
u/A
p were found to be quite variable. The values of ranged from 0.1807 to 0.4266;A
u/A
p ranged from 0.0089 to 0.4899. The values of andA
u/A
p correlated well (r = 0.6018;p<0.005) and the regression for andA
u/A
p was obtained: = (0.220 ± 0.016) + (0.340 ± O.06)A
u/A
p. The values of andA
u/A
p were then compared with complexity ratings, magnetic field strength, time, and . The quantities andA
u/A
p were found to be independent of the complexity, magnetic field strength, and time factors. The correlation between andA
u/A
p lead to the proposed division of into an umbral thermal contrast u, and a penumbral thermal contrast p. These values were calculated from the photometric data: u = 0.57 ± 0.01 and p = 0.26 ± 0.006. 相似文献
16.
Masaya Saitou 《Astrophysics and Space Science》1989,162(1):47-56
Some peculiarities in the behaviour of a model self-gravitating system described by hydrodynamical equations and isothermal equation of state connected with the presence of thermodynamical fluctuations in real systems were investigated in numerical experiment. The values of density and velocity , , respectively, were computed by numerical code perturbed on each time-step and in each computational cell by random values , for modeling such fluctuations. Perturbed values
i
=
i
+
i
,v
i
=
i
+ v
i
were used to initiate the next step of computations. This procedure is equivalent to an introduction into original hydrodynamical equations of Langevin sources which are random functions. It is shown that these small fluctuations (= v =0,2 =v
2 = 10–8) grow many times in marginally-stable state. 相似文献
17.
A. M. I. Osman 《Astrophysics and Space Science》1985,116(2):299-311
Surface photometry of the UV continuum galaxy NGC 838 has been carried out in theB, V system using photographic plates obtained with the 74 Kottamia telescope, Egypt. Isophotes, luminosity profiles, integrated photographic magnitudes, effective diameters and other photometric parameters are derived.The photoelectrically calibrated total apparent magnitudes areB
T
=13.57 with maximum diameters 1.57×1.34 (at threshold
m
=27.7 mag.//) andV
T
=12.91 with maximum diameters 1.54×1.32 (at threshold
m
=27.7 mag./). The integrated colour index(B–V)
T
=0.66 and the effective surface brightness
e
(B=19.0 mag./) and
e
(V=19.7 mag./. The major axis is at position angle =85°±1°.The nucleus of NGC 838 is quite blue (integrated colour(B–V)=0.41 forr
*<0.1) compared to normal galaxies while the colour becomes redder from the nucleus outwards. The UV excess, H emission and radio continuum emission previously observed from this galaxy by other investigators may be attributed to a recent burst of star formation in the nucleus of the galaxy of duration slightly greater than 2×107 yr. 相似文献
18.
Dimensional analysis is used to derive the distribution of solar flare energies,p() = A-3/2, in accordance with recent observational and numerical results. Several other scalings, notably
fl
2
, where fl is the flare duration, are obtained as well. 相似文献
19.
It is shown that escaping of solar flare energetic protons into interplanetary space as well as their relation to the flare gamma-ray emission depend on the parameter = 8p/B
0
2
, where p is the pressure of hot plasma and energetic particles and B
0 is the magnetic field in a flaring loop. If 1, the bulk of the energetic protons escape to the loss cone because of diffusion due to small-scale Alfvén-wave turbulence, and precipitate into the footpoints of the flaring loop. The flare then produces intense gamma-ray line emission and a weak flux of high energy protons in interplanetary space. If >*0.3-1.0, then fast eruption of hot plasma and energetic particles out of the flaring loop occurs, this being due to the flute instability or magnetic-field-plasma nonequilibrium. The flare then produces a comparatively weak gamma-radiation and rather intense proton fluxes in interplanetary space. We predict a modulation of the solar flare gamma-ray line emission with a period 1 s during the impulsive phase that is due to the MHD-oscillations of the energy release volume. The time lag of the gamma-ray peaks with respect to the hard X-ray peaks during a simultaneous acceleration of electrons and protons can be understood in terms of strong diffusion. 相似文献
20.
Chih Kang Chou 《Astrophysics and Space Science》1971,10(2):291-308
The reaction rates for the proton-proton reaction and the related electron capture reaction in a strongly magnetized relativistic electron gas of arbitrary degree of degeneracy are computed. The proton-proton reaction rates are unaffected by the presence of the magnetic field for field strengths up to the critical valueH
q
=m
2
c
3/e=4.414×1013G. For fields greater thanH
q
, the proton-proton reaction rates are enhanced linearly with (=H/H
q
).The PeP reaction is investigated in detail for a wide range of temperatures, densities and magnetic field strengths that are of interest. The main results are as follows: In the non-degenerate regime the reaction rates are significantly reduced for high temperatures (T
95) and low fields (1). For instance, pep(H)=0.04 pep(O) at =10–3,T
9=10. For relatively high fields (>1) and low temperatures (T
92), the reaction rates are enhanced approximately linearly with . In the complete degenerate regime the reaction rates are reduced up to one-third of the field-free value for moderate densities (6/e10). At high densities (6/e10) the reaction rates are unaffected by the magnetic field. 相似文献