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1.
Using the flux-transport equation in the absence of sources, we study the relation between a highly peaked polar magnetic field and the poleward meridional flow that concentrates it. If the maximum flow speed m greatly exceeds the effective diffusion speed /R, then the field has a quasi-equilibrium configuration in which the poleward convection of flux via meridional flow approximately balances the equatorward spreading via supergranular diffusion. In this case, the flow speed () and the magnetic field B() are related by the steady-state approximation () (/R)B()/B() over a wide range of colatitudes from the poles to midlatitudes. In particular, a general flow profile of the form sin p cos q which peaks near the equator (q p) will correspond to a cos n magnetic field at high latitudes only if p = 1 and m = n /R. Recent measurements of n 8 and 600 km2 s–1 would then give m 7 m s–1.  相似文献   

2.
The electro-optic deflector as an analyzer of circular polarization in the photoelectric magnetograph is described. The electro-optic deflector consists of an electro-optic crystal and a polarizing beamsplitter. The plane bifurcation of this beamsplitter coincides with the spectrograph dispersion direction. The beamsplitter bifurcates a spectral line in two components. The distance between them is 0. The photometer slit is situated between these components. Both components of Zeeman splitting fall on the photometer slit but the distance between them varies from 0 + 2 H to 0 – 2 H (where H is the Zeeman splitting) with the electric voltage frequency applied to the electro-optic crystal. The intensity variations at the photometer slit are proportional to 4 H .  相似文献   

3.
2800 Mgii (. 1). (N +/N 11000) , , (N +/N 110). , . —, , . — . : ; 0.002 1 , 0.1 ; () 100 –3; ; ; , 10 ; 10–4 1 . 2800 Mgii .  相似文献   

4.
As previously shown (Rabe, 1970), two classes of small periodic librations exist, in the plane, elliptic restricted problem, for an infinite sequence of easily specified oscillation frequenciesZ j . The present paper considers the dependence ofZ on the eccentricitye of the primary motion, in addition to its dependence on the mass parameter , and determines the resulting relations between ande, for any given periodic frequencyZ j . These relationships are obtained from the conditionD (Z j ,, e)=0, where the basic determinantD has been expanded up to terms of orderZ 20, 5, ande 4.Presented at the Conference on Celestial Mechanics, Oberwolfach, Germany, August 27–September 2, 1972.  相似文献   

5.
Ai-Hua  Zhou  Guang-Li  Huang  Xin-Dong  Wang 《Solar physics》1999,189(2):345-356
Two sets of accurate approximate expressions for the gyrosynchrotron radiation in the transverse propagation case are presented for the first time. They contain emissivity –/BNand absorptivity – B/Nfor e-mode, effective temperature T effand frequency of peak brightness p. The expressions are designed for the range 2 to 7 of electron energy spectral index and for the ranges from 2 to 10 and 10 to 100 of harmonic numbers s(=/B). Their statistical error is, respectively, ±18% and ±29% for –/BNand – B/Nfor 10/B100, ±128% and and ±170% for 2/B10.  相似文献   

6.
Green's Theorem is developed for the spherically-symmetric steady-state cosmic-ray equation of transport in interplanetary space. By means of it the momentum distribution functionF o(r,p), (r=heliocentric distance,p=momentum) can be determined in a regionr arrbwhen a source is specified throughout the region and the momentum spectrum is specified on the boundaries atr a andr b . Evaluation requires a knowledge of the Green's function which corresponds to the solution for monoenergetic particles released at heliocentric radiusr o , Examples of Green's functions are given for the caser a =0,r b = and derived for the cases of finiter a andr b . The diffusion coefficient is assumed of the form = o(p)r b . The treatment systematizes the development of all analytic solutions for steady-state solar and galactic cosmic-ray propagation and previous solutions form a subset of the present solutions.  相似文献   

7.
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   

8.
Summary Evolution of the orbital elements of a two-body system with slowly decreasing mass according to Jeans' mode is described by a non-linear, non-autonomous system of differential equations.In general the system contains one stationary solution (e=1,f=), for which an instability criterion is derived. For example the stationary solution is unstable for all Jeans-Eddington functionsm n (t) with 1n3 which characterize the loss of mass. Furthermore, it is possible to describe the quantitative behaviour ofE+,e anda for arbitrarym(t) in a large number of cases. In the case of the Jeans-Eddington functions we find that the amplitude of the oscillations ine is monotone decreasing with time ifn>3 and it is monotone increasing with time ifn<3.By comparing these analytical results with the numerical calculations of Hadjidemetriou we explain the rapid rotation of the line of apsides which occurs if the initial value ofe is nearly-circular.
, , . (e=1,f=), . , -m n (t), , 1n3. , E+,e a m(t) . - , , n>3, , n<3. , , - e.
  相似文献   

9.
We present the use of the analytical solutions of the planets and of the Moon's motion in the determination of the quantities which relate the barycentric and the geocentric coordinate systems and of the expressions of precession-nutation. The computation of the precession and nutation quantities are built with the analytical theories of the motion of the Moon, the Sun and the planets of the Bureau des longitudes. We take into account the influence of the Moon, the Sun and all the planets on the potential of the Earth limited to C j,0 for j from 2 to 5, C 2,2, S 2,2, C 3, S 3, , for from 1 to 3 and C 4,1, S 4,1. We determine the 3 Euler angles , , and 2 calculating the components of the torque of the external forces with respect to the geocenrer in the case of the rigid Earth. The equations are solved by iterations and so are taken into account the nutations-on-the-nutations effects. We have determined the analytical variations of the angles and w fixing the equator with respect to the ecliptic J2000. We find, in w, a secular term of –26.5026 mas per century. The analytical solution of the precession-nutation has been compared to a numerical integration over the time span 1900–2050. The differences do not exceed 16 µas for and 12 µas for .  相似文献   

10.
I. D. Palmer 《Solar physics》1973,30(1):235-242
A simple model of solar cosmic ray propagation which includes diffusion, convection, and energy loss by adiabatic deceleration is studied. A Monte Carlo technique is employed to investigate the variation of mean particle energy in the interplanetary medium after the impulsive release of mono-energetic particles at the Sun. At 1 AU typical energy losses are 43% at 20 h and 64% at 60 h after particle release for a diffusion coefficient (r)= 0r with =+1/2 and 0=1.33 × 1021 cm2 s–1. When 0 in this model is reduced by a factor of 4, the energy loss is greater by a factor of 2 at 60 h after particle release. When is increased, the energy losses are greater. Using the model parameters above, an increase in solar wind speed from 300 to 600 km s–-1 gives rise to energy losses that are greater again by factor of 2 at a time of 60 h. Results are compared with an observation by Murray et al. (1971) of a knee in the energy spectrum of solar protons. It is not considered likely that the change in the energy of the knee with time requires, in addition to adiabatic deceleration, another energy change process which acts to increase the energy of particles.Part of this work was performed while the author was at CSIRO, Division of Radiophysics, Epping, NSW, Australia; also supported in part by the U.S. Atomic Energy Commission.  相似文献   

11.
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   

12.
The componentsj andj of the current densityj are expressed in terms of the torsion and curvature of the magnetic lines of force and a relation between and equivalent to divj=0, is pointed out.Assuming that the magnetotail neutral line is not a straight line parallel to the (solar magnetospheric)y-coordinate and that loops of closed fieldlines may be formed in the distant magnetotail, we discuss the topological features of the corresponding current system. We find that the perpendicular current is diverted into the direction ofB and that enhancements and depletions ofj along the Sun-Earth line are generated. Arguments usual in current diversion analyses imply a possibility of disintegration of the magnetotail.It is ponted out that the simply connected surfaces containing both vectors,j andB, are unlikely to exist in the magnetotail. The concept of current sheets containing the vector lines ofB is mathematically, and consequently also physically, not feasible.  相似文献   

13.
Light-element abundances are compiled for six peculiar A stars (3 CenA, 2 CVn, HR 1732,v For, Cnc, and 112 Her) with Heilines very weak for their colours. The abundances are interpreted on the theory that peculiar A stars were once secondaries in binary systems in which the primaries exploded as type II supernovae. During the explosions of the primaries, protons were accelerated to high energies (>20 MeV) in shock waves at the secondaries, and spallation of He, C, N, and O occurred. This was followed by the arrival of heavier elements from the primaries. Abundances on 2 CVn, HR 1732, andv For were subsequently modified by surface nuclear reactions involving protons and -particles accelerated to lower energies (10 MeV), probably by magnetic fields. Successive (, ) reactions formed Si28 from Ne20, and (p, ) reactions acting on A40 and Ca40 may have contributed to the excesses of Cl observed on 2 CVn and HR 1732. These proposals have interesting implications with regard to the relative abundances of the iron-peak elements found on peculiar A stars and in the Solar System.  相似文献   

14.
A two-stage model of the propagation of 1–50 MeV solar-flare cosmic rays is presented. The first stage consists of a thin spherical shell of radius r a near the Sun which feeds particles into interplanetary space (the second stage) where they propagate along the Archimedean mean interplanetary magnetic field under the influences of anisotropic diffusion, convection, and energy changes. To calculate the time dependence at a fixed point in space, account is taken of the corotation of flux tubes past the observer.It is shown that the well-known east-west effect of the time-to-maximum cannot be obtained if the injection from the first stage is impulsive and thus a time and longitude dependent release for the second stage is essential. This is achieved by treating the first stage as a thin, spherical, diffusing shell of radius r a with diffusion coefficient s, from which particles leak into interplanetary space at a rate determined by the leakage coefficient .With this model we are able to reproduce simultaneously four principal features of solar events observed at r = 1 AU: (i) the east-west effect, i.e. the time-to-maximum as a function of flare longitude; (ii) the three phases of the anisotropy vector variation; (iii) the time-to-convective-phase as a function of flare longitude; and (iv) the longitudinal distribution of the differential intensity. Our best estimates of the parameters of the near-Sun propagation are that 0.01 hr–1 s/r a 2 0.02 hr–1 and 1/15 hr–1 1/10 hr–1. For the interplanetary propagation we estimate /V - 1.2AU with , the effective cosmic-ray diffusion coefficient and V, the solar-wind speed.  相似文献   

15.
A method of multi-cloud model (MCM) is proposed in this paper in order to research asymmetric profiles of spectral line formed by solar discrete active objects aligned along the line-of-sight difection. Based on the MCM method, under the conditions of certain assumptions and approximations, the line-of-sight velocityV and three other physical parameter approximation values, (i.e. Doppler width D , source functionS and optical depth at line center 0) within different clouds may be derived simultaneously by fitting both profiles theoretical and observational. An application example of the method withm=3 shows that MCM method is suitable to measure the velocity fields of multi-object at the same time from their non-Gaussian profiles of complex. TheV and D derived from the method are reliable,S and 0 are approximation. An influence of the variations of initial values in the parameter on the solution is given as well.  相似文献   

16.
The H observations of a selected sample of bright Be stars are presented. The available infrared observations at K band (2.2 m) of these stars have been used to find the infrared excess emission. The analysis of the combined data show thatL H, the luminosity of the H emission line, is proportional toL IR, the luminosity of the infrared excess emission. The linear correlation betweenL IR andL H shows that both the infrared excess and the H line originate in a common region. It is also detected that the infrared excess emission is produced throughout the whole envelope whereas the H is emitted in some defined region of the circumstellar (CS) envelope.  相似文献   

17.
All results, achieved up to now, show the long term stability of our planetary system, although, especially the inner solar system is chaotic, due to some specific secular resonances. We study, by means of numerical integrations, the dynamical evolution of the planetary system where we concentrate on the stability of motion of the terrestrial planets Venus, Earth and Mars. Our model consists of a simplified planetary system with the inner planets Venus, Earth and Mars as well as Jupiter and Saturn. A mass factor was introduced to uniformly change the masses of the terrestrial planets; Jupiter and Saturn were involved in the system with their actual masses. We integrated the equations of motion with a Lie-integration method for a time interval of 107 years. It turned out that when 220 < < 245 and > 250 the system became unstable due to the strong interactions between the planets. We discuss the model planetary systems for small mass-factors 0.5 10 and large ones 160 270 with the aid of several different numerical tools. These results can be applied to recently discovered exoplanetary systems, which configuration is comparable to our own.  相似文献   

18.
The diagramV - log(1 +z e ) as function of (, ) is considered for the quasars. HereV is the apparent visual magnitude,z e is the emission line redshift, and are the equatorial coordinates. Two opposite extreme spots NE and SE are observed on the sky, where the inclination of the straight line fitting the dependenceV - log(1 +z e ) is maximum and minimum. The coordinates of the centres of these extreme spots are ( NE, NE) = (282°, +42°) and ( SE, SE) = (70°, -38°) with errors 5°. A hypothesis of the Superattractor (SA) is proposed to explain such an effect. Two independent tests of this hypothesis are realized. First, the dependence or the frequency a of the absorbers in QSO spectra on (, ) is investigated. A region of the larger a is found. The coordinates of its centre are (, ) = (82°, - 10°) with error 5°. Second, the cases ofz a >z e are plotted in the Mercatorial projection (, ). The most of the casesz -z e > 0.02 are concentrated within the circle with radiusR = 34° and centre (, ) = (50°, - 15°). The both anomalous regions overlap the Southern extreme spot around SE. The SA direction is (, ) = (67°, -21°) with errors about 12°. The redshift of SA isz SA = 1.7 ± 0.3 that corresponds to the distancer SA = (3100 ± 300)h –1 Mpc for the Hubble constantH 0 = 75h kms–1 Mpc–1. The SA mass isM SA ~ 1018-1020 M . The orientation of the normal to the quasiperiodical large-scale sheet structure on the sky occurs near SA.  相似文献   

19.
, (1962, 1963) . , (1) (2) .  相似文献   

20.
A search for low energy neutrinos of all flavours in correlation with 553 ray bursts detected by BATSE aboard the Compton Observatory has been performed by the LSD (Liquid Scintillator Detector) neutrino telescope. No excess ofe,, orv e,, candidate has been detected by LSD during the time interval in which BATSE detected the 90% of the photon flux for any of the GRBs analyzed. Upper limits on the neutrino fluxes are given in the paper.  相似文献   

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