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1.
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
2.
Recent progress in modeling ionospheric current systems requires global conductivity models which can reflect substorm conditions on an instantaneous basis. For this purpose, empirical relations of the North-South component (ΔH) of the magnetic disturbance field observed at College with the Pedersen (Σp) and Hall (ΣH) conductivities deduced from the Chatanika radar data and their ratio () are examined. These empirical formulas allow us to construct approximate distribution patterns of Σp and Σ>H over the entire polar region on the basis of the distribution of ΔH at given instants by devising an appropriate weighting function for both the polar cap and the subauroral region. The global conductivity distributions thus obtained are compared with those employed by Kamide et al. (1981) and Spiro et al. (1982). The comparisons show that the gross features are similar among them. In addition, we also examine the relationship of ΔH with the North-South component of the electric field with the particle energy injection rate (uA) estimated from the Chatanika radar data. Based on the empirical relation between ΣH and uA the global distribution of the latter over the entire polar region at particular instants can also be obtained. 相似文献
3.
Altitude distributions of electronically excited atoms and molecules of oxygen and nitrogen in the aurora have been obtained by means of rocket-borne wavelength scanning interference filter photometers launched from Fort Churchill, Manitoba (58.4°N, 94.1°W) on January 23, 1974. Atomic oxygen densities derived from mass spectrometer measurements obtained during the flight are used in conjunction with the volume emission rate ratio of the N2(C3Πu?B3Πg) (0-0) second positive and N2(A3Σu+, v = 1?X1Σg+) Vegard-Kaplan bands to derive a rate constant for quenching of the N2(A3Σu+, v = 1) level with O(3P) of 1.7(±0.8) × 10?11 cm3 s?1 These data, together with O den derived from the O2(b1Σg+) state nightglow emission observed during the rocket ascent, suggest that quenching of the N2(A3Σu+, v = 1) level by O2 has a significant positive temperature dependence. The processes involved in the production and loss of the N2(A3Σu+) state are considered and energy transfer from the N2(A3Σu+) state to O(3P) is found to be a significant source of the OI 5577 Å green line in this aurora at altitudes below 130 km. Emission from the NO(A2Σ+?X2Π) gamma bands was not detected, an observation which is consistent with the mass spectrometer data obtained during the flight indicating that the NO density was <108 cm3 at 110 km. On the basis of previous rocket and satellite measurements of the NO gamma bands, energy transfer from the N2(A3Σu+) state to NO(X2Π) is shown to be an insignificant source of the gamma bands in aurora. Altitude profiles of the N2(a1Πg?X1Σg+) Lyman-Birge-Hopfield band system are presented. 相似文献
4.
Hot spots similar to those in the radio galaxy Cygnus A can be explained by the strong shock produced by a supersonic but classical jet \(\left( {u_{jet}< c/\sqrt 3 } \right)\) . The high integrated radio luminosity (L?2×1044 erg s?1) and the strength of mean magnetic field (B?2×10?4 G) suggest the hot spots are the downstream flow of a very strong shock which generates the ultrarelativistic electrons of energy ?≥20 MeV. The fully-developed subsonic turbulence amplifies the magnetic field of the jet up to 1.6×10?4 G by the dynamo effect. If we assume that the post-shock pressure is dominated by relativistic particles, the ratio between the magnetic energy density to the energy density in relativistic particles is found to be ?2×10?2, showing that the generally accepted hypothesis of equipartition is not valid for hot spots. The current analysis allows the determination of physical parameters inside hot spots. It is found that:
- The velocity of the upstream flow in the frame of reference of the shock isu 1?0.2c. Radio observations indicate that the velocity of separation of hot spots isu sep?0.05c, so that the velocity of the jet isu jet=u 1+u sep?0.25c.
- The density of the thermal electrons inside the hot spot isn 2?5×10?3 e ? cm?3 and the mass ejected per year to power the hot spot is ?4M 0yr?1.
- The relativistic electron density is less than 20% of the thermal electron density inside the hot spot and the spectrum is a power law which continues to energies as low as 30 MeV.
- The energy density of relativistic protons is lower than the energy density of relativistic electrons unlike the situation for cosmic rays in the Galaxy.
5.
To supplement a rocket investigation of the auroral green line, data from some auroral pulsations have been analyzed by direct integration of the time-dependent continuity equations for each of the sources now thought to contribute. It is shown that indirect processes are not incompatible with studies of auroral pulsations, and that a non-negligible contribution to the green-line intensity comes from dissociative recombination. Calculations using the theoretical O(1S) lifetime show that the remaining green line must come from a direct or very fast process; however, if the O(1S) lifetime can be reduced, significant portions of the green line can come from the transfer of energy from N2(A3Σu+) to atomic oxygen. 相似文献
6.
V.A. Krasnopolsky 《Planetary and Space Science》1981,29(9):925-929
The excitation, energy transfer and quenching of O2 (A3 Σu+, C3 Δu, c1 Σu?) and O(1S) are discussed, taking into account laboratory measurements and observations on the airglow of the Earth, Venus and Mars. The excitation of O(1S) occurs by the Barth mechanism with O2(c) as a precursor: the rate coefficient is 2.5 × 10?12 cm3 s?1 for υ > 0 and 2.5 × 10?12 exp() cm3 s?1for υ = 0. The O2(c) can be formed directly by recombination or by O2(A) and O2(C) colliding with other molecules; the O2(c) yield through quenching of these states is about 0.3 in air and about 1.0 in carbon dioxide. The rate coefficients of some processes that control the molecular oxygen bands and the atomic oxygen green line are estimated. 相似文献
7.
It is proposed that energy transfer from excited O2 contributes to the production of O(1S) in aurora. An analysis is presented of the OI5577 Å emission in an IBC II+ aurora between 90 and 130 km. The volume emission rate of the emission at these altitudes is consistent with the production rate of O(1S) by energy transfer to O(3P) from N2 in the A3Σ2+ state and O2 in the A3Σu+, C3Δc1Σu? states, the N2A state being populated by direct electron impact excitation and B → A cascade and the excited O2 states by direct excitation. Above the peak emission altitude (~105 km), energy transfer from N2A is the predominant production mechanism for O(1S). Below it, the contribution from quenching of the O2 states becomes significant. 相似文献
8.
We have obtained center-to-limb photoelectric spectra of the CN(1,1) B-X bandhead region λ3868–3872 Å at Kitt Peak National Observatory. From these spectra and a detailed analysis of the formation of the CN (1, 1) spectrum we derive a best-fit upper photospheric model differing from the HSRA which is consistent with our previous CN(0, 0) λ3883 spectra. We derive a solar carbon abundance of log A c = 8.30 ± 0.10 compared to the HSRA value of log A c = 8.55 ± 0.10. In addition we specify the regions of formation for the CN(0, 0) λ3883.35 and CN(1, 1) λ 3871.38 bandheads at disc center and limb. 相似文献
9.
Zhi-yao Yu 《Astrophysics and Space Science》2003,283(1):43-52
An important observational parameter of the OH megamasers is their 18 cm main line intensity ratio R(H)=T
1667
/T
1665. The R(H) of only 56OH megamasers from the 90 extragalactic objects is found. We have found, log R(H) is correlated with log L(OH). Using (Henkel and Wilson,1990)'s model the optical depths of 1667 MHz maser line of 56 OHmegamasers have been obtained. Here we test the hypothesis that the opacity of a maser should be related to its luminosity,
for which data from the 56 OH megamaser sources can be taken. We have also found that log (-τ) is correlated with log L(OH).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
We have detected new HD absorption systems at high redshifts, z
abs = 2.626 and z
abs = 1.777, identified in the spectra of the quasars J0812+3208 and Q1331+170, respectively. Each of these systems consists
of two subsystems. The HD column densities have been determined: log N
HDA = 15.70 ± 0.07 for z
A = 2.626443(2) and log N
HDB = 12.98 ± 0.22 for z
B = 2.626276(2) in the spectrum of J0812+3208 and log N
HDC = 14.83 ± 0.15 for z
C = 1.77637(2) and log N
HDD = 14.61 ± 0.20 for z
D = 1.77670(3) in the spectrum of Q1331+170. The measured HD/H2 ratio for three of these subsystems has been found to be considerably higher than its values typical of clouds in our Galaxy.We
discuss the problem of determining the primordial deuterium abundance, which is most sensitive to the baryon density of the
Universe Ωb. Using a well-known model for the chemistry of a molecular cloud, we have estimated the isotopic ratio D/H=HD/2H2 = (2.97 ± 0.55) × 10−5 and the corresponding baryon density Ωb
h
2 = 0.0205−0.0020+0.0025. This value is in good agreement with Ωb
h
2 = 0.0226−0.00060.0006 obtained by analyzing the cosmic microwave background radiation anisotropy. However, in high-redshift clouds, under conditions
of low metallicity and low dust content, hydrogen may be incompletely molecularized even in the case of self-shielding. In
this situation, the HD/2H2 ratio may not correspond to the actual D/H isotopic ratio. We have estimated the cloud molecularization dynamics and the
influence of cosmological evolutionary effects on it. 相似文献
11.
A statistical study of the dependence of the star formation rate in the nuclear regions of 39 Kazarian galaxies on the integral
parameters of these galaxies is carried out on the basis of spectra from SDSS DR6. The value of SFR/kpc2 for our sample lies in the range 0.013÷2.04M
⨀ year−1kpc−2 (with the maximum value of 2.04 corresponding to the Kaz 98 (merger)). It is found that the surface density of the rate of
star formation correlates positively with the bar structure parameter and EW(Hα), and that, for spiral galaxies of early morphological types, SFR/kpc2 is greater than for the later types. It is shown that the color B-R for the galaxies and the color (u − g)
nucl
for the nuclear region correlate positively with the total absorption A(Hα) in the Ha line for the nuclear region. The average value of A(Hα) for our samples is found to be A(Hα)=1.3±0.09 magnitudes.
Translated from Astrofizika, Vol. 52, No. 2, pp. 211–224 (May 2009). 相似文献
12.
E. A. Baranovskii S. A. Musorina V. P. Tarashchuk 《Bulletin of the Crimean Astrophysical Observatory》2014,110(1):85-89
Sunspot spectra for LiI 6708Å lines and for several FeI and CaI lines were obtained. Observations were performed in January and in August, 2011 using the TST-2 telescope with a charge-coupled camera at the Crimean Astrophysical Observatory. The sunspot models were calculated by using the observing profiles of FeI and CaI lines. Lithium abundance was determined by using the calculated sunspot models and LiI 6708Å observed profiles; this equals log(N Li) = 0.98 and 0.95 (in the scale logA(H) = 12.0). 相似文献
13.
A new value of the solar photospheric abundance of iron, independent of line-shape parameters, is derived. Our analysis is based on a study of 40 weak infrared lines (0.85<λ<2.5 μ) for which theoretical oscillator strengths (calculated with configuration interactions taken into account) have recently been computed by Kurucz (1974). The abundance obtained, A Fe = 7.57±0.11 (in the usual scale where log N H = 12.00) is in agreement with the ‘high’ solar values recently reported in the literature and with the meteoritic abundance. 相似文献
14.
The stars in the Main Sequence are seen as a hierarchy of objects with different massesM and effective dynamical radiiR eff=R/α given by the stellar radii and the coefficients for the inner structure of the stars. As seen in a previous work (Paper I), during the lifetime in the Main SequenceR eff(t) remains a near invariant when compared to the variation in the time ofR(t) and α(t). With such an effectiveR eff one obtains the amounts of actionA c(M), the effective densities ρeff(M)=ρ(M)α3(M), the densities of action and of energy (or mean presures in the stellar interior)a c(M),e c(M), and the potential energiesE p(M). The amounts of action areA c∝M k withk≈1.87 for the M stars,k≈5/3 for the KGF stars, andk≈1.83 for the A and earlier stars, representing very simples conditions for the other dynamical parameters. For instancek≈5/3 means a near invariant effective density αeff for the KGF stars, while for such stars the mean densities and coefficients α present the strongest variations with masses ρ(M)∝M ?1.81, α(M)∝M0.6. The cases for the M stars (e c(M)∝M ?1) and for the A and earlier stars (betweena c(M)=constant and αeff(M)∝M ?1) and also discussed. These conditions for the earlier stars also represent reasonable mean values for the whole stellar hierarchy in the range of masses 0.2M ⊙≤M≤25M ⊙. With all this, one can build ‘dynamical’ HR diagrams withA c(M), Ep(M), αeff M ?p , etc., whose characteristics are analogous to these in the photometrical HR diagram. A comparison is made betweenA c(M) from the models here and the HR diagram with the best known stars of luminosity classes IV, V, and white dwarfs. The comparison of the potential energiesE p(M)∝M ?p according to the stellar models used here and the observed frequency function ψ(M∝M ?q (number of stars in a given interval of masses) from different authors suggests the possibility that the productE p(M)ψ(M) is a constant, but this must be confirmed with further studies of the function ψ(M) and its fine structure. There are analogies between the formulation used here for the stellar hierarchy and other physical processes, for instance, in modified forms of the Kolmogorov law of turbulence and in the formulation used for the hierarchy of molecular clouds in gravitational equilibrium. Besides, the function of actionA c(M) for the stars has analogous properties to the relations of angular momenta and massesJ(M) for different types of objects. The cosmological implications of all this are discussed. 相似文献
15.
Until now a simple Photometric Sunspot Index (PSI) model was used (e.g. Willsonet al., 1981) to describe the contribution of sunspots to the solar irradiance deficit measurement by ACRIM. In this work we replace this model by a photometry of sunspot pictures for the period of 19 August to 4 September, 1980 taking into account the individual features, like lightbridges or umbral dots, of each spot. The main results of this preliminary analysis are: (1) theA
u/A
p ratios and alsos the values vary in a wide range and are by no means constant as in the PSI model; (2) the general trend of the irradiance deficit from our analysis agrees well with the ACRIM measurements; (3) on some days there are differences of more than 50% between the deficits derived from our measurements and from the PSI model.Paper presented at the 11th Eurpean Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain 相似文献
16.
V. V. Kovtyukh C. Soubiran S. I. Belik M. P. Yasinskaya F. A. Chekhonadskikh V. Malyuto 《Kinematics and Physics of Celestial Bodies》2008,24(3):171-175
We used high-resolution echelle spectra with high signal-to-noise ratio to determine with a high degree of accuracy some atmospheric parameters (T eff, log g and [Fe/H]) for 68 non-variable supergiants of types F, G, and K and 26 classical Cepheids in 302 pulsation phases. Very accurate effective temperatures, with errors of only 10–30 K, were determined by the line-depth ratio method. We found that the observed intrinsic color indices (B ? V)0 can be related to these parameters: (B ? V)0 = 57.984? 10.3587(log T eff)2 + 1.67572(log T eff)3 ? 3.356 log g+ 0.321 V t + 0.2615[Fe/H] + 0.8833log g(log T eff). With this empirical relation, the intrinsic colors of individual supergiants and classical Cepheids of spectral types F0-K0 and of luminosity classes I and II can be estimated with an accuracy as high as 0.05 m , which is comparable to the accuracy of the most elaborate photometric procedures. In view of large distances to supergiants, the method we propose here allows a large-scale mapping of interstellar extinction with an accuracy of 0.1–0.2 m in a quite large region of the Galaxy. 相似文献
17.
In this research paper, we have derived the formula for both the changes in energy (δE) and entropy (δS) and thereafter calculated the change in entropy (δS) with corresponding change in energy (δE) taking account the first law of the black hole mechanics relating the change in mass M, angular momentum J, horizon area A and charge Q, of a stationary black hole, when it is perturbed, given by formula satisfying in the vacuum as
dM = \frack8p dA + WdJ - udQ\delta M = \frac{k}{8\pi} \delta A + \Omega\delta J - \upsilon\delta Q, specially for Non-spinning black holes. 相似文献
18.
A perturbation in the ratio of the matter temperature to the radiation temperature in the form of a Gaussian with amplitude
A and width σ (in units of the redshift z) centered at some redshift z
c is considered, with some “standard” temperature ratio obtained from a simultaneous solution of the cosmological recombination
kinetics and energy equations being taken as the initial (unperturbed) one. Comparatively small (A = ± 0.01), fast (σ = 17) perturbations are shown to give rise to distinct narrow absorption (for A > 0) or emission (for A < 0) quasi-lines in each of the subordinate continua. The positions of these quasi-lines correlate with the position of the
perturbation center, while their intensities are very sensitive to the perturbation amplitude. At the same time, the manifestation
of the perturbation is much less clear in hydrogen lines (subordinate ones and the Ly-α line) and two-photon emission. As a result, the full perturbed spectrum is characterized by the presence of the narrow quasi-lines
mentioned above and by a general decrease (for A > 0) or increase (for A < 0) in intensity with increasing wavelength. 相似文献
19.
Compressible homogeneous spheres with constant adiabatic index γ were studied for their dynamical stability by Chandrasekhar
and he found that for each value of u (≡ mass to size ratio), there is a value of γ = γc, such that for γ < γc, the configuration is dynamically unstable. On examining the properties of the Chandrasekhar's spheres (homogeneous spheres
with constant γ) it is found that these spheres are non-isentropic, and the speed of sound within these spheres is finite.
The authors find that (i) for the causality condition to be fulfilled throughout the configuration, the value of γ ≤ [2/(surface
redshift)], (ii) for a given value of u, the binding coefficient, αr = (Mr -M)/M, vanishes for some value of γ = γb and for all the values of γ < γb the configurations are unbound, and (iii) for u≤ (1/3), one can find configurations which are bound, dynamically stable, and the speed of sound is less than that of light
throughout the configuration, whereas, for u >(1/3), the physically viable models of homogeneous density distribution are not possible. If the configuration is considered
to be isentropic, then both γ and the speed of sound become infinite throughout the configuration.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
The correlation between the ratio of the global irradiation to the extraterrestrial solar radiation (H/H
0), and the ratio of the ultraviolet solar irradiation to the extraterrestrial solar radiation (H
u
/H
0) on a horizontal surface at Bahrain (=26°), and some terrestrial and solar parameters (the monthly average relative humidity, temperature, relative sunshine duration, cosmic radiation intensity, and sunspot number) have been studied. Moreover, the role of the solar effects and the terrestrial effects on the global and the solar ultraviolet radiation has been studied. A detailed investigation has been carried between the level of the cosmic radiation received at Bahrain and the sunspot number. It was concluded that as the solar activity increases, cosmic radiation and sunspot number play a predominant effect on the correlation of (H/H
0) and (H
u
/H
0). Furthermore, the correlation between cosmic radiation and sunspot number also increases. 相似文献