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1.
D3 and H pictures of prominences were obtained with a 21-in. Lyot coronograph and a Fabry-Perot etalon used as a narrow band filter. The monochromatic images of quiescent, quasiquiescent and loop-prominences were studied. The comparison of the isophotes of quiescent and quasi-quiescent prominences in D3 with those in H shows the similarity of the prominence structure at both wavelength, although there is a strong tendency for an increase in the intensity ratio D3/H in the upper region of prominences. It seems that it is due to lower temperature in the upper regions of prominences. Probably, the relaxation processes establishing ionization equilibrium play some role. Measurements of the knot intensities of the loop-prominence show strong variations of the intensity ratio D3/H (more than one order of magnitude). 相似文献
2.
3.
-- () ., , , , , . , , . , . 相似文献
4.
5.
G. A. Krasinsky 《Celestial Mechanics and Dynamical Astronomy》1972,6(1):60-83
The general conception of the critical inclinations and eccentricities for theN-planet problem is introduced. The connection of this conception with the existence and stability of particular solutions is established. In the restricted circular problem of three bodies the existence of the critical inclinations is proved for any values of the ratio of semiaxes . The asymptotic behaviour of the critical inclinations as 1 is investigated.
. . . 1.相似文献
6.
, . () . , , , . ( ), , , . . (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
7.
An analysis of the effects of Hall current on hydromagnetic free-convective flow through a porous medium bounded by a vertical plate is theoretically investigated when a strong magnetic field is imposed in a direction which is perpendicular to the free stream and makes an angle to the vertical direction. The influence of Hall currents on the flow is studied for various values of .Nomenclature
c
p
specific heat at constant pressure
-
e
electrical charge
-
E
Eckert number
-
E
electrical field intensity
-
g
acceleration due to gravity
-
G
Grashof number
-
H
0
applied magnetic field
-
H
magnetic field intensity
- (j
x
, j
y
, j
z
)
components of current densityJ
-
J
current density
-
K
permeability of porous medium
-
M
magnetic parameter
-
m
Hall parameter
-
n
e
electron number density
-
P
Prandtl number
-
q
velocity vector
- (T, T
w
, T
)
temperature
-
t
time
- (u, v, w)
components of the velocity vectorq
-
U
0
uniform velocity
-
v
0
suction velocity
- (x, y, z)
Cartesian coordinates
Greek Symbols
angle
-
coefficient of volume expansion
- e
cyclotron frequency
-
frequency
-
dimensionless temperature
-
thermal conductivity
-
coefficient of viscosity
-
magnetic permeability
-
kinematic viscosity
-
mass density of fluid
- e
charge density
-
electrical conductivity
- e
electron collision time 相似文献
8.
Computations of polarization and intensity of radiation from a unit stellar surface area are presented, as well as a study of the numerical characteristics of atmospheres — single-scattering albedo and the initial source function(), which define the polarization behaviour of atmospheres. The radiatively stable models of stellar atmospheres presented by Kuruczet al. (1974) and Kurucz (1979) have been used for calculations. Since the versus optical depth dependence is rather weak, it has been assumed that (=cost. With a fixed effective temperatureT
eff maximum values of are characteristic of stars featuring the lowest surface gravity accelerationg. Among stars with radiatively stable atmospheres, maximum values of (=5000 Å) 0.4–0.6 are exhibited by supergiants withT
eff=8000–20 000 K. The plot of () is characterized by discontinuities at the boundaries of spectral series for hydrogen and, sometimes, for helium. Maximum are attained in the Lyman region of =912–1200 Å, where can reach the value 0.7–0.9 for supergiants, this value being 0.3 for Main-Sequence stars. For stars withT
eff 35 000 K, high values of also are attained for <912 Å. Within the infrared region, is always small because of bremsstrahlung absorption.A rapid growth of the source functionB
with < typical for ultraviolet range (within the Wien part of spectrum), together with high values of results in the strong polarization of emission from a unit stellar surface element, sometimes exceeding the values for the case of a pure electron scattering. For longer wavelengths, where the limb-darkening coefficient is smaller, the plane of polarization abruptly turns 90° in the central parts of the visible stellar disk. 相似文献
9.
A. A. Boyarchuk T. S. Belyakina A. E. Tarasov Yu. V. Glagolevski 《Astrophysics and Space Science》1987,131(1-2):775-780
The profiles of the emission lines of H HeI 5876 and HeII 5411 in the spectrum of AG Peg obtained in the minimum of 1985 are described. The light curves in UBVRI system are presented. No indication for the presence of a magnetic field exceeding the error of observations (200 gauss) has been found.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986. 相似文献
10.
An exact analysis of the effects of mass transfer on the flow of a viscous incompressible fluid past an uniformly accelerated vertical porous and non-porous plate has been presented on taking into account the free convection currents. The results are discussed with the effects of the Grashof number Gr, the modified Grashof number Sc, the Schmidt number Sc, and the suction parametera for Pr (the Prandtl number)=0.71 representating air at 20°C.Nomenclature
a
suction parameter
-
C
species concentration
-
C
species concentration at the free stream
-
g
acceleration due gravity
- Gc
modified Grashof number (vg*(C
–C
)/U
0
3
)
- Pr
Prandtl number (C
p/K)
-
T
temperature of the fluid near the plate
-
T
dimensionless temperature near the plate ((T-T
)/(T
-T
))
-
U(t)
dimensionless velocity of the plate (U/U
0)
-
v
normal velocity component
-
v
0
suction/injection velocity
-
x, y
coordinate along and normal to the plate
-
v
kinematic viscosity (/gr)
-
C
p
specific heat at constant pressure
-
C
w
species concentration at the plate
-
C
non-dimensional species concentration ((C-C
)/(C
w
-C
))
- Gr
Grashof number (g(T
w
-T
)/U
0
3
)
-
D
chemical molecular diffusivity
- K
thermal conductivity
- Sc
Schmidt number (/D)
-
T
w
temperature of the plate
-
T
free stream temperature
-
t
time variable
-
t
dimensionless time (tU
0
2
/)
-
U
0
reference velocity
-
u
velocity of the fluid near the plate
-
u
non-dimensional velocity (u/U
0)
-
v
dimensionless velocity (v/U
0)
-
v
0
non-dimensionalv
0
(v
0
/U0)=–at–1/2
-
y
dimensionless ordinate (yU
0/)
-
density of the fluid
-
coefficient of viscosity 相似文献
11.
We report here on high angular resolution observations of solar noise storm sources at a frequency of 75 MHz. The data for the study were obtained at the Gauribidanur Radio Observatory (long.: 77°2612 E, lat.: 13°3612 N) about 100 km north of Bangalore, India, during the solar eclipse of 24 October 1995. Our main conclusion is that there are structures of angular size 2.5 arc min in the outer solar corona. 相似文献
12.
S. Ferraz-Mello C. Beaugé T. A. Michtchenko 《Celestial Mechanics and Dynamical Astronomy》2003,87(1-2):99-112
Numerical simulations of the evolution of planets or massive satellites captured in the 2/1 and 3/1 resonances, under the action of an anti-dissipative tidal force. The evolution of resonant trapped bodies show a richness of solutions: librations around stationary symmetric solutions with aligned periapses ( = 0) or anti-aligned periapses ( = ), librations around stationary asymmetric solutions in which the periapses configuration is fixed, but with taking values in a wide range of angles. Many of these solutions exist for large values of the eccentricities and, during the semimajor axes drift, the solutions show turnabouts from one configuration to another. The presented results are valid for other non-conservative anti-dissipative forces leading to adiabatic convergent migration and capture into one of these resonances. 相似文献
13.
C. Martin Gaskell 《Astrophysics and Space Science》1982,82(1):247-248
The reported correlation between the absorption-line of emission-line redshifts of quasars is shown to be due to selection effects and thus to favour neither the intrinsic nor intervening hypotheses for the origin of quasar absorption lines. 相似文献
14.
The stability analysis of several stronglynon-homogeneous, self-gravitating, one-dimensionalunstable equilibrium systems is carried out with the help of numerical techniques. The evolution of the perturbed unstable equilibria is studied by following the motion of the boundary curves of water bag configurations defining the systems.It is found that initial perturbations drive the unstable equilibrium states out of equilibrium at rates depending on the typical scale length of the perturbations : the instability rates increase with . 相似文献
15.
Formulae containing the elements of the variational matrix are obtained which determine the linear iso-energetic stability parameters of periodic orbits of the general three-body problem. This requires the numerical integration of the variational equations but produces the stability parameters with the effective accuracy of the numerical integration. The procedure is applied for the determination of horizontally critical orbits among the members of sets of vertical-critical periodic orbits of the threebody problem. These critical-critical orbits have special importance as they delimit the regions in the space of initial conditions which correspond to possibly stable three-dimensional periodic motion of low inclination. 相似文献
16.
J. F. Valdés-Galicia G. Wibberenz J. J. Quenby X. Moussas G. Green F. M. Neubauer 《Solar physics》1988,117(1):135-156
In the quasi-linear theory of pitch angle scattering the power spectrum of magnetic field fluctuations is related to the shape of the pitch angle diffusion coefficient D(), the absolute value of the mean free path , and the rigidity dependence of the mean free path (R). We discuss these relations in detail during the solar particle event of 11 April, 1978 which was observed on HELIOS-2 at a distance of 0.49 AU from the Sun. Magnetic field measurements obtained during the time of the event are used as a basis for the layer model in which the method of particle trajectories in an actually measured field is used to simulate pitch angle diffusion. The values of D() and based on the trajectory simulation for 100 MeV protons (field approach) are compared with results obtained from solar proton data (particle approach) and with predictions from quasi-linear theory based on the additional assumption of the slab model for magnetic field fluctuations (QLT approach). The time of the event is characterized by a high level of field fluctuations, the observed mean free path of about 0.03 AU for 100 MeV protons is smaller than the average value near 1 AU. Results from the field and particle approaches agree surprisingly well. The remaining difference in the mean free path of about a factor of 2 could be due to tangential discontinuities which are measured by the magnetometer, but not seen by the real particles traveling along the average field. The results from the field and QLT approaches based on the same set of magnetic field measurements differ by about a factor of 4. One of the reasons for this discrepancy is that the conditions for resonance scattering are only marginally valid. In addition, the wave vectors representing Alfvén-type fluctuations may not be totally field aligned. This deviation from the slab model would cause an increase of the theoretically predicted mean free path and lead to better agreement with the other two approaches. 相似文献
17.
An essential part in the mechanics under study is taking into consideration the effect of motions of the Universe objects upon that of an individual one surrounded by them including those infinitely far from it. Only macro-objects of the Universe are meant here.
Zusammenfassung Ein wesentlicher Bestandteil der Mechanik unter unserer Betrachtung ist die Berechnung des Einflusses auf die Bewegung eines individuellen Objektes von Bewegungen der Universum Objekte die es umringen einschließlich jene Objekte, die unendlich entfernt sind. Nur Makroobjekte des Weltalles sind in der Absicht dabei.
, . .相似文献
18.
O. A. Golubchina 《Solar physics》1995,160(1):207-212
The recent modernization of the RATAN-600 radio telescope at the Special Astrophysical Observatory has provided an opportunity to develop new procedures, called relay and zoned relay, for utilizing the new cone-surface secondary reflector. The geometric area, the horizontal beamwidth spatial resolution, and the permissible radiometer bandwidth are discussed. We are also able to estimate the changes in the sensitivities of the radio telescope-radiometer systems. The new procedures, called relay and zoned relay, allow us to obtain two-dimensional images of radio objects and to track the development of rapidly varying sources in any azimuth.Presented at the CESRA-Workshop on Coronal Magnetic Energy Release at Caputh near Potsdam in May 1994. 相似文献
19.
. . .
, 相似文献
Transfer of resonance radiation in infinite medium is considered as a process of random walks of photons. Close relation is shown to exist between the problems of transfer of line radiation and the stable distributions of the probability theory. This relation is used as a basis of a new method for the investigation of the asymptotic properties of the radiation field far from the sources.
, 相似文献
20.
, 1-, 2- 3- . , . 相似文献