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1.
We have determined for the first time a spectroscopic orbit for WX Cnc. The orbital elements are V0 = +9.8 km/s, k1 = 110.2 km/s, K2 = 149.0 km/s, To = HJD 2446 480.0309. After combining with the published photometric results, we derive the the following absolute parameters: A = 6.32R, R1 = 1.53R, R2=1.18R, M1 = 1.29 M, M2 = 0.96M. The spectroscopic mass-ratio is q = 0.74.  相似文献   

2.
It is greatly expected that the relic neutrino background from past supernovae will be detected by Superkamiokande (SK) which is now under construction. We calculate the spectrum and the event rate at SK systematically by using the results of simulations of a supernova explosion and reasonable supernova rates. We also investigate the effect of a cosmological constant, Λ, on the spectrum, since some recent cosmological observations strongly suggest the existence of Λ. We find following results. (1) The spectrum has a peak at about 3 MeV, which is much lower than that of previous estimates (6–10 MeV). (2) The event rate at SK in the range from 10 MeV to 50 MeV, where the relic neutrinos from past supernovae are dominant, is about 25h502(RSN/0.1 yr−1)(nGh50−3/0.02 Mpc−3) events per year, where RSN is the supernova rate in a galaxy, nG is the number density of galaxies, and h50 = H0/(50 km/s Mpc), where H0 is the Hubble constant. (3) The event rate is almost insensitive to Λ. The flux increases in the low energy side (< 10 MeV) with increasing Λ, but decreases in the high energy side (> 10 MeV) in models in which the integrated number of supernovae in one galaxy is fixed.  相似文献   

3.
Inspection of recent spectra presented by Sivjee (1983) show evidence of the 0–4 and 0–5 bands of the N2(c′41Σu+ → a1Πg) Gaydon-Herman system. In conjunction with earlier spectra, it is now possible that this band system is a significant auroral component, with an intensity approx. 7% that of the N2 2P system. The absence in aurorae of the potentially far stronger N2(c′41Σu+ → X1Πg) system is discussed. It is that the O2(A3Σu+ → X3Σg−) band system is indiscernible in Sivjee's auroral spectra, under conditio the foreground nightglow is expected to be clearly visible. On the other hand, at least one relatively strong O2(A′3Δu → a1Δg) band appears to be present in these spectra.  相似文献   

4.
太阳大气锂的丰度７Ｌｉ／Ｈ＝１０－１１（按原子数计）。或［７Ｌｉ］＝ｌｏｇ（７Ｌｉ／Ｈ）＋１２＝１０．它比太阳系原始星云和银河系星际介质钾的丰度要低约两个数量级．因此太阳在它形成之后，其大气锂必定经受了严重衰减．然而年轻的银河疏散星团（如昂星团和英仙ａ星团）中有效温度高于５５００ Ｋ的主序星，其锂丰度都基本是正常的，井末呈现明显的衰减．这充分说明，太阳型恒星锂的衰减主要发生在主序阶段，而非在主序前的演化阶段． 在恒星中，７Ｌｉ是通过核反应７Ｌｉ（ｐ，ａ）４Ｈｅ，而毁坏．上述反应在Ｔ≥ ２．５×１０…  相似文献   

5.
The surface temperature of a rotating, charged body is found separately under the Kerr-Newman metric and the vector graviton metric. Particular reference is made to pulsars. It is found that, 1) under the Kerr-Newman metric, the surface temperature rises from the poles to the equator, when the radius R of the body is greater than a certain critical value, rn. When R= rn, the surface temperature is uniform. When R < rn, the above gradient is reversed. For pulsars, the equatorial temperature is some 3 × 104 K higher than the polar temperature. 2) Under the Vector graviton field metric, a similar temperature differential exists, but it is much smaller in size.  相似文献   

6.
The evolution of the cosmic ray primary composition in the energy range 106–107 GeV (i.e. the “knee” region) is studied by means of the e.m. and muon data of the Extensive Air Shower EAS-TOP array (Campo Imperatore, National Gran Sasso Laboratories). The measurement is performed through: (a) the correlated muon number (Nμ) and shower size (Ne) spectra, and (b) the evolution of the average muon numbers and their distributions as a function of the shower size. From analysis (a) the dominance of helium primaries at the knee, and therefore the possibility that the knee itself is due to a break in their energy spectrum (at EkHe=(3.5±0.3)×106 GeV) are deduced. Concerning analysis (b), the measurement accuracies allow the classification in terms of three mass groups: light (p,He), intermediate (CNO), and heavy (Fe). At primary energies E0≈106 GeV the results are consistent with the extrapolations of the data from direct experiments. In the knee region the obtained evolution of the energy spectra leads to: (i) an average steep spectrum of the light mass group (γp,He>3.1), (ii) a spectrum of the intermediate mass group harder than the one of the light component (γCNO2.75, possibly bending at EkCNO≈(6–7)×106 GeV), (iii) a constant slope for the spectrum of the heavy primaries (γFe2.3–2.7) consistent with the direct measurements. In the investigated energy range, the average primary mass increases from lnA=1.6–1.9 at E01.5×106 GeV to lnA=2.8–3.1 at E01.5×107 GeV. The result supports the standard acceleration and propagation models of galactic cosmic rays that predict rigidity dependent cut-offs for the primary spectra of the different nuclei. The uncertainties connected to the hadronic interaction model (QGSJET in CORSIKA) used for the interpretation are discussed.  相似文献   

7.
The existence of sidereal semidiurnal variation of cosmic-ray intensity in a rigidity region 102-103 GV has been reported by many researchers, but there is no consensus of opinion on its origin. In this paper, using the observed semidiurnal variations in a rigidity range (300–600 GV) with 10 directional muon telescopes at Sakashita underground station (geog. lat. = 36°, long. = 138°E, DEPTH = 80 m.w.e.), the authors determine the magnitudes (η1, η2) and directions (a1, a2) of the first- and second-order anisotropies in the following galactic cosmic-ray intensity distribution (j)
jdp = j0{1 + η1P1(cos χ1) + η2P2(cos χ2)}dp
, where Pnis the nth order spherical function and χn is the pitch angle of cosmic rays with respect to an. For the determination, the influence of cosmic-ray's heliomagnetospheric modulation, geomagnetic deflection and nuclear interaction with the terrestrial material and also of the geometric configuration of the telescopes are taken into account. Usually, the semidiurnal variation is produced by the second-order anisotropy. The present observation, however, requires also the first-order anisotropy which usually produces only the diurnal variation, but can produce also the semidiurnal variation as a result of the heliospheric modulation. The first- and second-order anisotropies are characterized with η1) > 0 and η2 < 0 have almost the same direction (a1 a2) specified by the right ascension ( 0.75 h) and declination (δ 50°S) and, therefore, they can be expressed, as a whole, by an axis-symmetric anisotropy of loss-cone type (i.e. deficit intensities in a cone). It is noteworthy that this anisotropy approximately coincides with that inferred from the air shower observation at Mt Norikura in the rigidity region 104 GV.  相似文献   

8.
Intensified Reticon spectra have been obtained at a high dispersion for the Algol system, RT Persei. They were measured by the cross-correlation technique. The spectroscopic elements, revised for the primary component and determined for the secondary for the first time, are: T0 = HJD 2,446,038.9332, K1 = 55.0, K2 = 194.7, V0 = −8.3 km/s. A mass ratio q = m2/m1 = 0.282 is deduced. A circular orbit is adopted. The spectrum of the primary is F5V, and the secondary is a subgiant. With the elements determined here and the published photometric parameters, the absolute dimensions of the binary are: A = 4.20, R1 = 1.20, R2 = 1.08 R; M1 = 1.08, M2 = 0.30 M.  相似文献   

9.
Recent rocket observations of the N2 V-K (Vegard-Kaplan) system in the aurora have been reinterpreted using an atmospheric model based on mass spectrometer measurements in an aurora of similar intensity at the same time of year. In contrast to the original interpretation, we find that population by cascade from the C3Πu and B3Πg states in the A3Σu+v=0,1 levels, as calculated using recently measured electron excitation cross sections, accurately accounts for the observed relative emission rates (IV-K/12PG0.0). In addition there is no need to change the production rate of A 3 Σ u+ molecules relative to that of C3Πuv=0 as a function of altitude in order to fit the profile of the deactivation probability to the atmospheric model. Quenching of A 3 Σ u+ molecules at high altitudes is dominated by atomic oxygen. The rate constants for the v=0 and v=1 levels are 8 × 10−11 cm3 sec−1 and 1.7 × 10−10 cm3 sec−1 respectively, as determined using the model atmosphere mentioned above. Recent observations with a helium cooled mass spectrometer suggest that conventional mass spectrometer measurements tend to underestimate the atomic oxygen relative concentration. The rate coefficients may therefore be too large by as much as a factor of 3. Below 130 Km we find that it is possible to account for the deactivation in bright auroras by invoking large nitric oxide concentrations, similar to those recently observed mass spectrometrically and using a rate constant of 8 × 10−11 cm3 sec−1 for both the v=1 levels. This rate constant is very nearly the same as that measured in the laboratory (7 × 10−11 cm3 sec−1). Molecular oxygen appears not to play a significant role in deactivating the lower A 3 Σ u+ levels.  相似文献   

10.
If neutrinos have mass, we give reasons for a possible pattern of three (squaed) mass eigenvalues: m12 (2.8−5.8) (eV)2, m22 0.01 (eV)2, m32 (1.5−1) × 10−4 (eV)2. The flavor states νμ and νe are mixtures of the eigenstates with m2 and m3 with a significant mixing, corresponding to an effective mixing angle of about 0.45. The ντ is nearly the state with m1; the other two effective mixing angles are about an order of magnitude smaller than 0.45. There is a marked similarity to mixing in the quark sector.  相似文献   

11.
The method of identifying absorption line systems in QSO spectra (Cui et al. 1983; Chen et al. 1983) is further developed here. Certain limitations of the method and their improvements are discussed. Certain other problems requiring further study are pointed out. The improved method is applied to PKS 0528-250, and gives two new absorption line systems Za = 0.065 and 0.0345 in addition to the four systems Za = 2.8110, 2.8130, 2.5275, 2.1410, consistent with the systems A1A2, B, C of Norton et al. (1980). However, the systems D1, D2, E, F and G of Chen and Norton (1984) are not recovered. The reason for this discrepancy is discussed.  相似文献   

12.
When the local solar zenith angle, χL, is < 105° the 6300 A line is much stronger than expected on the basis of F region ionic recombination alone. Between 95 and 105° the additional intensity is quantitatively explained by production of O(1D) from photolysis of O2 in the Schumann-Runge continuum, (λλ 1300–1750 A) using current values for solar flux, atmospheric composition and quenching of O(1D) by N2. The Schumann-Runge (SR) component exhibits a large seasonal variation with a maximum in summer. We interpret this variation as implying a seasonal change in thermospheric O2 abundance; the change seems largely to reflect a variation in O2 density at the base of the diffusive regime although some contribution may come from changes in thermospheric temperature structure. Large changes in the SR component exist from day to day and with a 27 day period following a major magnetic storm. The photodissociation source becomes inadequate when xl < 95°; at 90° more than half of the intensity comes from still another source which we identify as local photoelectron excitation of O atoms.  相似文献   

13.
Correlation of cosmic-ray intensity (I) with the solar magnetic field expanded into the spherical surface harmonics, Bns(n 9), by Hoeksema and Scherrer has been studied using the following regression equation:
, where are subgroups of Bns classified in ascending order of n, and τi is the time lag of I behind correlation coefficient between the observed and simulated intensities (Iobs, Isml) in the period 1976–1985 is 0.87 and considerably better than that derived from any single index of solar activity. The lag time τ3 is greater than others, indicating that the higher order magnetic disturbances effective to the cosmic-ray modulation have a longer lifetime in space than the lower order disturbances. The rigidity spectrum of the cosmic-ray intensity variation responsible for AI due to the dipole moment is harder than those for others (A2,A3), indicating that the lowest order (i.e. largest scale) magnetic disturbances can modulate cosmic rays more effectively than the higher order disturbances. As another result of the present analysis, it has been found that the intensity depends also on the polarity of the polar magnetic field of the Sun; the residual (Iobs−Isml) of the simulation changes its sign from positive to negative with a time lag (0–5 Carrington rotation periods) behind the directional change of the solar magnetic dipole moment from northward to southward, and has a softer rigidity spectrum than AiS. The dependence is consistent with the result having been obtained in the previous period, 1936–1976, by one (K.N.) of the present authors. The polarity dependence can be found also in the 22-year variation of the time lags obtained every solar cycle in the period 1936–1985. The theoretical interpretation of these polarity dependences is discussed on the basis of the diffusion-convection-drift model.  相似文献   

14.
Using a non-local theory of convection, we calculated the structure of the solar convection zone, paying special attention to the detailed structure of the lower overshooting zone. Our results show that an extended transition zone exists near the bottom of the convection zone, where the temperature gradient turns smoothly from adiabatic in the convection zone to radiative in solar interior. A super-radiative temperature region is found in the overshooting zone under the solar convection zone, where     ,     ,     and     . The extension of the super-radiative region (defined by     l is about 0.63  H P (0.053 R⊙). A careful comparison of the distribution of adiabatic sound speed and density with the local one is carried out. It is found, strikingly, that the distribution of adiabatic sound speed and density of our model is roughly consistent with the results of reversion from solar oscillation observations.  相似文献   

15.
We calculate the event rates induced by a 51Cr νe source and by a 90Sr---90Y source in BOREXINO through elastic scattering on electrons, assuming a nonzero neutrino magnetic moment μν. We consider a source activity of about 2 MCi and estimate the solar ν (“source-off”) background for various oscillation scenarios. It is shown that values of μν as low as 0.5 × 10−10μB ( 0.2 × 10−10μB) can be proved with the 51Cr source (90Sr source) in about 100 days of data taking.  相似文献   

16.
N. Hiotelis   《New Astronomy》2002,7(8):531-539
We present density profiles, that are solutions of the spherical Jeans equation, derived under the following two assumptions: (i) the coarse grained phase-density follows a power-law of radius, ρ/σ3 ∝ r−, and (ii) the velocity anisotropy parameter is given by the relation βa(r)=β1+2β2 (r/r*)/[1+(r/r*)2] where β1, β2 are parameters and r* equals twice the virial radius, rvir, of the system. These assumptions are well motivated by the results of N-body simulations. Density profiles have increasing logarithmic slopes γ, defined by γ=−d ln ρ/d ln r. The values of γ at r=10−2.5rvir, a distance where the systems could be resolved by large N-body simulations, lie in the range 1.0–1.6. These inner values of γ increase for increasing β1 and for increasing concentration of the system. On the other hand, slopes at r=rvir lie in the range 2.42–3.82. A model density profile that fits well the results at radial distances between 10−3rvir and rvir and connects kinematic and structural characteristics of spherical systems is described.  相似文献   

17.
A numerical analysis of cyclotron instabilities is carried out by computing the dispersion relation for a three component cold plasma-beam system. Rates of growth and damping for various values of the stream density are calculated from the dispersion relation. The rates of growth and damping increase monotonically as the number density of the proton stream increases. It is found that the frequencies at the rates of maximum growth and the damping decrease slightly to lower frequencies and a sharp peak at these frequencies becomes blunt. The minimum e-folding times of an ion cyclotron wave for (a) σs = 10−4, σi = 10−2 and (b) σs = 10−1, σi = 10−2 are about 3·84 and 0·16 sec respectively in the vicinity of the equatorial plane at 6 Re, where σs and σi are the ratios of the beam density Ns and the helium ion (H6+) density Ni to the total positive ions in the plasma-beam system.  相似文献   

18.
The eigen-vibrational frequencies of Xiong Da-run's nonlocal and local convection models of solar envelope are calculated and compared. The differences between the observational and theoretical vibrational frequencies are less than 1%. They can be divided into two isolated groups. For modes with l ≥ 60, all the differences between observed and theoretical eigen-vibrational frequencies are distributed in a narrow and inclined belt in the (Δv ≈ v)-diagram. This shows that the theoretical model of solar convective region can approximately reflect the intrinsic structure of the sun in the region of r = (0.70–0.95)R. The discrepancies between the theoretical and observational frequencies come from the outer layers. For modes with l < 60, the theoretical vibrational frequency is smaller than the observational one. This implies that the temperature of the upper part of the convectively unstable region is rather low. The frequency difference is more dispersed in the local convection model than in the nonlocal convection model. For the intermediate- and low-frequency ranges (v < 3000), the difference between the two models is small, while for the high-frequency range (v ≥ 3000) the frequency in the local model is higher than in the nonlocal model. This means that the temperature of the radiation region beneath the convective region is higher in the local convection model than in the nonlocal convection model. The nonlocal model is nearer to the observation than the local model.  相似文献   

19.
From the photometric and spectroscopic data on AA UMa obtained by us in 1987 and 1986 and using the Wilson-Devinney program, we made a simultaneous solution. We found mass-ratio q = 1. 8157 ± 0.0099, M1 = 0.85 M, M2 = 1. 55 M , A = 3.39 R , R1 = 1.50 R , and degree of over-contact f = 0.15 ± 0.01. Adding six minimum times obtained by us to the literature, a new epoch formula is derived: Min.I(J.D.Hel) = 2 446 885.1119+0.468 125 83 E.  相似文献   

20.
In this paper, we study the galactic distribution and luminosity function of OH/IR maser sources. All the selected OH/IR sources have optical or infrared identification. Most of them are associated with late-type (>M5) Mira variables. Their derived density distribution shows a steep peak at a galactocentric distance of r0-7.5 kpc and decreases rapidly at smaller and larger R0. The FWHM of the distribution curve is 2.1 kpc. This is similar to the galactic distribution of Mira variables investigated by Glass et al.

We also derive the luminosity function of the identified OH/IR maser sources from their distances, their detection probabilities, and their corrected OH radio peak flux densities. The luminosity function ρ(L) varies as LOH−1.79. This is similar to that of unidentified maser sources. The range of luminosity of identified OH/IR sources is approximately from 0.16 Jy · kpc2 to 1000 Jy · kpc2. It is quite different from that of unidentified OH sources.

Finally, we discuss some differences and relations between identified and unidentified OH/IR maser sources.  相似文献   


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