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1.
The Lyα forest absorption lines in the spectra of quasars are interpreted as caused by the crossings of the light beam with the walls of a bubble structure (expanding with the Hubble flow only). Then, the typical separation between the absorption lines is proportional to the mean size of the bubbles. The variable factor is the expansion rate H[z]. The Friedmann regression analysis of the observed line separations determines the density parameter ω0 and the normalized cosmological term λ0 = λc2/3H20 of the appropriate cosmological model: ω0 = 0.014 ± 0.002, λ0 = 1.080 ± 0.006. Depending on the Hubble parameter this method reveals the values of the present mean matter density pm,0 = 2.6 h2 · 10−28 kg m−3 and of the cosmological constant Λ = 3.77 h2 · 10−52 m−2 (with h = H0/(100 km/s·Mpc)). According to our analysis all models with Λ = 0 must be excluded. The curvature of space is positive. The curvature radius R0 is 3.3 times the Hubble radius (c/H0). The age t0 is 2.8 times the Hubble age (H0−1).  相似文献   

2.
For the first time, height profiles of the stratospheric negative ion composition are presented. The results are from two nights of balloon borne mass spectrometers and cover an altitude range from 23.8 to 38.9 km. Below approx. 30km, NO?3 · mHNO3 ions are dominant. These are replaced by HSO4? · nH2SO4 · oHNO3 ions above this height. There are indications that the most abundant ions above 32 km have masses greater than 280 atomic mass units (amu), the instruments' mass range. The fractional ion count rates as a function of altitude are presented and their significance for neutral trace gas analysis and ion sampling is discussed.  相似文献   

3.
The Weinberg relation (which connects the Hubble constantH to the mass of a typical elementary particle) is an empirical relation hitherto unexplained. I suggest an explanation based on the Zel'dovich energy tensor of vacuum in a Robertson-Walker universe with constant deceleration parameter,q = const. This model leads to
  1. the Weinberg relation,
  2. a varying cosmological term Λ scaling asH 2,
  3. a varying gravitational constantG scaling asH,
  4. a matter creation process throughout the universe at the rate 10?47 g s?1 cm3,
  5. a deceleration parameter in the range -1 to 1/2, which allows a horizon-free universe and makes the lawG/H = constant, consistent with the Viking lander data on the orbit of planet Mars.
  相似文献   

4.
We review different surveys, in the optical and infrared, conducted in the very young (age 1–8 Myr), nearby (d ~ 350 pc) σ Orionis cluster aimed to characterize the substellar population. We describe spectral characteristics of very low mass stars, brown dwarfs and planetary mass objects in the cluster with spectral types from K7 to T6. We study the spatial distribution of the substellar population detected in a IZJ survey covering an area of 1.12 deg.2 We find that the radial distribution of substellar objects can be well fitted by an exponential law (ρ = ρo e ?r/ro ), with a central density (ρ o ) of 0.26 ± 0.03 objects/arcmin2 and a characteristic radius (r o) of 8.8 arcmin ± 0.6 (equivalent to 0.90 ± 0.06 pc at the distance of the cluster). We discuss the presence of possible inhomogeneities in this distribution due to the existence of subclustering. We also compare the spatial distribution of the substellar population with previously known stars in the cluster. We report the initial mass spectrum in the substellar domain.  相似文献   

5.
In 2003–2008, highly accurate photoelectric and CCD observations of the close binary system DI Her were performed in the V band. The light curves of three primary and three secondary eclipses were constructed. These observations, along with the highly accurate photoelectric observations of other authors obtained in different years from 1963 to 1986, have confirmed the difference between the observed (1 . o 3 ± 0 . o 1/100 yr) and theoretical (4 . o 3/100 yr) rates of apsidal motion. Our photometric data are indicative of a possible variability in the system with period P′ = 1.175 days and amplitude A′ = 0 . m 011, which is probably related to the pulsations of one of the components. There may be a third body in the system that produces in-phase variations in the times of primary and secondary minima with a period of 10.5 yr and an amplitude of 1 . m 5.  相似文献   

6.
Measured rates are presented for the reaction of He+ ions with H2 (and D2) molecules to form H+, H2+, and HeH+ ions, as well as for the subsequent reactions of H+ and HeH+ ions with H2 to form H3+. The neutralization of H3+ (and H5+) ions by dissociative recombination with electrons is shown to be fast. The reaction He+ + H2 is slow (k = 1.1 × 10?13 cm3/sec at300°K) and produces principally H+ by the dissociative charge transfer branch. It is concluded that there may be a serious bottleneck in the conversion of two of the primary ions of the upper Jovian ionosphere, H+ and He+ (which recombine slowly), to the rapidly recombining H3+ ion (α[H3+]?3.4 × 10?7 cm3/sec at 150°K).  相似文献   

7.
It is the purpose of this paper to illustrate the interrelation between the problems of the ‘missing mass’, the galactic age and the cosmological constant A (or its equivalent quantum vacuum densityρ v ). The inflationary picture of the early universe predicts that our present universe should have a very nearlyEuclidean metric. If we accept this concept, one would have to discriminate between two rather extreme Euclidean cosmological models:
  1. The standard model with ∧=0 and a densityρ c = 3H 0 2 G. There are difficulties ifH 0≥5- km s?1 Mpc?1 and the galactic aget 0≥14×109 years.
  2. The Euclidean Friedmann-Lemaître models with ∧>0, i.e., Δgt;0, i.e.,ρ v =ρ c ?ρ o , whereρ o is the present matter density, including the nonrelativistic dark matter. Hereρ v ‘competes’ with the missing mass.
Measurements of apparent diameters of galaxies up to redshifts of 2 will permit one to discriminate between the models provided that size evolution of galaxies can be determined or neglected (see Figure 3).  相似文献   

8.
The present paper outlines a cosmological paradigm based upon Dirac’s large number hypothesis and continual creation of matter in a closed static (nonexpanding) universe. The cosmological redshift is caused by the tired-light phenomenon originally proposed by Zwicky. It is shown that the tired-light cosmology together with continual matter creation has a universal Hubble constant H 0=(512π 2/3)1/6(GC 0)1/3 fixed by the universal rate C 0 of matter creation, where G is Newton’s gravitational constant. It is also shown that a closed static universe has a finite age τ 0=(243π 5/8GC 0)1/3 also fixed by the universal rate of matter creation. The invariant relationship H 0 τ 0=3π 261/2 shows that a closed static universe is much older (≈one trillion years) than any expanding universe model based upon Big-Bang cosmology. It is this property of a static universe that resolves any cosmic age crisis provided that galaxy formation in the universe is a continual recurring process. Application of Dirac’s large number hypothesis gives a matter creation rate C 0=4.6×10?48 gm?cm?3?s?1 depending only on the fundamental constants of nature. Hence, the model shows that a closed static universe has a Hubble constant H 0=70 km?s?1?Mpc?1 in good agreement with recent astronomical determinations of H 0. By using the above numerical value for H 0 together with observational data for elongated cellular-wall structures containing superclusters of galaxies, it is shown that the elongated cellular-wall configurations observed in the real universe are at least one hundred billion years old. Application of the microscopic laws of physics to the large-scale macroscopic universe leads to a static eternal cosmos endowed with a matter-antimatter symmetry. It is proposed that the matter-antimatter asymmetry is continuously created by particle-antiparticle pair annihilation occurring in episodic cosmological gamma-ray bursts observed in the real universe.  相似文献   

9.
The possibility of H3+ playing a role as a sink for noble gases has been investigated in the case of Argon. Elaborate quantum methods (ab initio Coupled Cluster and density functional BH&HLYP levels of theory) have been shown to reproduce the rotational constants within 0.3% together with the only known IR frequency on the test case of Ar…D3+. Dissociation energies of (Ar)n…H3+ as a function of cluster size, i.e. 7.2 (n=1), 3.7 (n=2), 3.6 (n=3), 1.6 (n=4), 1.7 (n=5) kcal/mol, follow the pattern established experimentally for (Ar)n…H3+ and (H2)n…H3+ series. Rotational constants and harmonic frequencies of (Ar)n…H3+ (n=1-3) are presented.  相似文献   

10.
Measured fractional abundances for stratospheric positive ions are reported for the first time. The measurements which were obtained from balloon-borne ion mass spectrometer experiments relied on recent simulation studies of electric field induced cluster ion dissociation conducted at our laboratory.The ion abundance data provide strong support for identifications of the observed ions as H+(H2O)n and Hx+xL(H2O)m proposed previously. Moreover, it is found that x most likely cannot be identified as NaOH or MgOH which implies that gaseous metal compounds do not exist in the middle stratosphere in significant abundances.Implications of the present findings for the composition and chemistry of stratospheric ions as well as for stratospheric aerosols are discussed.  相似文献   

11.
A radiative seasonal model which incorporates a multilayer radiative transfer treatment at wave-lengths longward of 7 μm is presented and applied to Saturn's stratosphere. Opacities due to H2-He, CH4, C2H2, and C2H6 are included. Season-dependent insolation is shown to produce a strong hemispheric asymmetry decreasing with depth at the Voyager encounter times, and seasonal amplitudes of 30°K at the poles are predicted in the high stratosphere. The ring-modulated dependence of the insolation and the orbital eccentricity are shown to have a significant effect. Calculations agree closely with the Voyager 1 and 2 radio occultation ingress profiles recorded at 76°S and 36.5°S for CH4/H2 = 3.5 + 1.4/? 1.0 × 10?3;the estimated errors include modeling systematic errors and uncertainties in the occultations profiles. The possible role of aerosols in the stratospheric heating is analyzed. The Voyager 2 egress profile recorded at 31°S cannot be reproduced by calculations. Some constraints on the C2H2 and C2H6 abundances are derived. The upper portion of the occultation profiles (p < 3mbar) can be matched for C2H2/H2 = 1.0 + 1.3/?0.6 × 10?7, C2H6/H2 = 1.5 + 1.8/?0.9 × 10?6 at 76°S and C2H2/H2 = 4 + 6/?4 × 10?8, C2H6/H2 = 6 + 9/?6 × 10?7 at 36.5°N. At the northern occultation latitude, the discrepancy with the concentrations derived from analysis of IRIS spectra by R. Courtin, D. Gautier, A. Marten, B. Bézard, and R. Hanel (1984, Astrophys. J.287) can be explained by a sharp variation of the mixing ratios of these gases with altitude in the upper stratosphere. Other interpretations are discussed.  相似文献   

12.
We report on spectro-imaging infrared observations of Jupiter's auroral zones, acquired in October 1999 and October 2000 with the FTS/BEAR instrument at the Canada-France-Hawaii Telescope. The use of narrow-band filters at 2.09 and 2.12 μm, combined with high spectral resolution (0.2 cm−1), allowed us to map emission from the H2S1(1) quadrupole line and from several H3+ lines. The H2 and H3+ emission appears to be morphologically different, especially in the north, where the latter notably exhibits a “hot spot” near 150°-170° System III longitude. This hot spot coincides in position with the region of increased and variable hydrocarbon, FUV and X-ray emission, but is not seen in the more uniform H2S1(1) emission. We also present the first images of the H2 emission in the southern polar region. The spectra include a total of 14 H3+ lines, including two hot lines from the 3ν2-ν2 band, detected on Jupiter for the first time. They can be used to determine H3+ column densities, rotational (Trot) and vibrational (Tvib) temperatures. We find the mean Tvib of the v2=3 state to be lower (960±50 K) than the mean Trot in v2=2 (1170±75 K), indicating an underpopulation of the v2=3 level with respect to local thermodynamical equilibrium. Rotational temperatures and associated column densities are generally higher and lower, respectively, than inferred previously from ν2 observations. This is a likely consequence of a large positive temperature gradient in the sub-microbar auroral atmosphere. While the signal-to-noise is not sufficient to take full advantage of the 2-D capabilities of the observations, the search for correlations between line intensities, Tvib and column densities, indicates that variations in line intensities are mostly due to correlated variations in the H3+ column densities. The thermostatic role played by H3+ at ionospheric levels may provide an explanation. The exception is the northern “hot spot,” which exhibits a Tvib about 250 K higher than other regions. A partial explanation might invoke a homopause elevation in this region, but a fully consistent scenario is not yet available. The different distributions of the H2 and H3+ emission are equally difficult to explain.  相似文献   

13.
On three nights in February 1976 we carried out polarimetric measurements, in V, of the short periodic eclipsing binary XY UMa, covering a complete cycle. The results are as follows:
  1. Within all phase intervals the linear polarization does not exceed 0.1%.
  2. In the phase range 0 p .95–1 p .35 the scatter of the Stokes parametersQ andU is about twice that within the phase interval 0 p .35–0 p .95.
  3. A periodogram analysis of these data revealed a period of 21000 s, which is equal to half the orbital periodP o=0d.47899 within 1.5%.
From these we derive the conclusions that no circumstellar envelope can be made responsible for the observed long-term changes of the light curve and system brightness, supporting the earlier spectroscopic finding. The different scatter of the Stokes parameters at different phase intervals and theP o/2 periodicity are in favor of the star spot model for XY UMa proposed by one of the authors (E. G.).  相似文献   

14.
Paul G. Steffes 《Icarus》1985,64(3):576-585
Microwave absorption observed in the 35- to 48-km-altitude region of the Venus atmosphere has been attributed to the presence of gaseous sulfuric acid (H2SO4) in that region. This has motivated the laboratory measurement of the microwave absorption at 13.4- and 3.6-cm wavelengths from gaseous H2SO4 in a CO2 atmosphere under simulated conditions for that region. As part of the same experiments, upper limits on the saturation vapor pressure of gaseous H2SO4 have also been determined. The measurements for microwave absorption have been made in the 1- to 6-atm pressure range, with temperatures in the 500 to 575°K range. Using a theoretically derived temperature dependence, the best-fit expression for absorption from gaseous H2SO4 in a CO2 atmosphere at the 13.4-cm wavelength is 9.0 × 109 q(P)12T?3 (dB km?1), where q is the H2SO4 number mixing ratio, P is the pressure in atmospheres, and T is the temperature in degrees Kelvins. The best-fit expression for absorption at the 3.6-cm wavelength is 4.52 × 1010q(P)0.85T?3 (dB km?1). The inferred H2SO4 vapor pressure above liquid H2SO4 corresponds to ln p = 8.84 ? 7220/t where p is the H2SO4 vapor pressure (in atm) and T is the temperature in degrees Kelvins. These results suggest that abundances of gaseous H2SO4 on the order of 15 to 30 ppm could account for the microwave absorption observed by radio occultation experiments at 13.3- and 3.6-cm wavelengths. They also suggest that such abundances would correspond to saturation vapor pressure existing at or above the 46- to 48-km range, which correlates with the observed cloud base. It is suggested that future measurements of absorption in the 1- to 3-cm wavelength range will provide additional tools for monitoring variations in H2SO4 abundance via radio occultation and radio astronomical observations.  相似文献   

15.
The problem of the ionospheric formation in the Jovian upper atmosphere is examined. By adopting two plausible atmospheric models, we solve coupled time-dependent continuity equations for ions H2+, H5+, H+, H3+ and HeH+ simultaneously. It is shown that both radiative and three body association of H+ to H2 are important for the determination of the structure of the Jovian ionosphere. The maximum electron density in the daytime is found to be about 105 cm?3. It is also shown that diurnal variation with large-amplitude can exist in the Jovian ionosphere.  相似文献   

16.
Clusters of galaxies are approximated by the Schwarzschild interior solution (with non-zero cosmological constant) embedded in a Robertson/Walker background. The conditions that the two metrics join up smoothly and that the cluster be stable imply either (a)k=?1 with Λ lying in the range ?1.1×10?27?Λ?1.5×10?36 (s?2), or (b)k=0. Also, superclustering on a scale larger than 0.5 Mpc is unacceptable unless Λ<0.  相似文献   

17.
This paper describes a new method of solution of the time-dependent continuity and momentum equations for H+ and O+ in mid-latitude magnetic field tubes from the F-region to the equator. For each ion the equations are expressed as an integro-differential equation. This equation is treated as an ordinary differential equation and solved by a searching method. By means of this method, the distribution of H+ in the O+?H+ transition region and the protonosphere can be investigated and the influence of H+ fluxes on the F layer examined.As an example of application of the method a suggestion by Park (1971) about observed night-time enhancements of NmF2 is examined. He suggested that lowering of the F layer some hours after a magnetic substorm may cause NmF2 to increase because of increased ion influx from the protonosphere. In the present calculations the Flayer is maintained around a constant height for some time and then abruptly lowered. Under the conditions adopted the resulting increase in downward H+ flux is sufficient to maintain NmF2 against the increased recombination but not to increase NmF2 significantly. It is emphasised that these results are not conclusive.  相似文献   

18.
Images of Comet West in atomic hydrogen (1216 Å) emission were obtained from a sounding rocket on 1976 March 5.5 (R = 0.38 AU). The hydrogen production rate derived from the fit of a simple radial-outflow model to the observed inner isophotes was 3.2 × 1030 atoms/sec. The outer isophotes did not fit the predictions of the complex dynamic model of Keller and Meier, partly because of optical depth effects, but also because the nucleus was breaking up at about this time and it is quite possible that additional hydrogen was being emitted from smaller chunks of the nucleus distributed along the orbit. The above production rate, taken with data on C and O obtained simultaneously by Feldman and Brune, gives QH: Qo: Qc = 8:3.5:1. For Comet Kohoutek we obtained the ratio 7:1.7:1. The difference, if real, may be due to minor differences in composition or evolution, but in any case it appears that the two comets are similar.  相似文献   

19.
Europa's surface is chemically altered by radiolysis from energetic charged particle bombardment. It has been suggested that hydrated sulfuric acid (H2SO4·nH2O) is a major surface species and is part of a radiolytic sulfur cycle, where a dynamic equilibrium exists between continuous production and destruction of sulfur polymers Sx, sulfur dioxide SO2, hydrogen sulfide H2S, and H2SO4·nH2O. We measured the rate of sulfate anion production for cyclo-octal sulfur grains in frozen water at temperatures, energies, and dose rates appropriate for Europa using energetic electrons. The measured rate is GMixture(SO42−)=fSulfur (r0/r)βG1 molecules (100 eV)−1, where fSulfur is the sulfur weight fraction, r is the grain radius, r0=50 μm, β≈1.9, and G1=0.4±0.1. Equilibrium column densities N are derived for Europa's surface and follow the ordering N(H2SO4) » N(S)>N(SO2)>N(H2S). The lifetime of a sulfur atom on Europa's surface for radiolysis to H2SO4 is τ(−S)=120(r/r0)β years. Rapid radiolytic processing hides the identity of the original source of the sulfurous material, but Iogenic plasma ion implantation and an acidic or salty ocean are candidate sources. Sulfate salts, if present, would be decomposed in <3800 years and be rapidly assimilated into the sulfur cycle.  相似文献   

20.
Results of the scattered solar radiation spectrum measurements made deep in the Venus atmosphere by the Venera 11 and 12 descent probes are presented. The instrument had two channels: spectrometric (to measure downward radiation in the range 0.45 < γ < 1.17 μm) and photometric (four filters and circular angle scanning in an almost vertical plane). Spectra and angular scans were made in the height range from 63 km above the planet surface. The integral flux of solar radiation is 90 ± 12 W m?2 measured on the surface at the subsolar point. The mean value of surface absorbed radiation flux per planetary unit area is 17.5 ± 2.3 W m?2. For Venera 11 and 12 landing sites the atmospheric absorbed radiation flux is ~15 W m?2 for H >; 43 km and ~45 W m?2 for H < 48 km in the range 0.45 to 1.55 μm. At the landing sites of the two probes the investigated portion of the cloud layer has almost the same structure: it consists of three parts with boundaries between them at about 51 and 57 km. The base of clouds is near 48 km above the surface. The optical depth of the cloud layer (below 63 km) in the range 0.5 to 1 μm does not depend on the wavelength and is ~29 and ~38 for the Venera 11 and 12 landing sites, respectively. The single-scattering albedo, ω0, in the clouds is very close to 1 outside the absorption bands. Below 58 km the parameter (1 ? ω0) is <10?3 for 0.49 and 0.7 μm. The parameter (1 ? ω0) obviously increases above 60 km. Below 48 km some aerosol is present. The optical depth here is a strong function of wavelength. It varies from 1.5 to 3 at λ = 0.49 μm and from 0.13 to 0.4 at 1.0 μm. The mean size of particles below the cloud deck is about 0.1 μm. Below 35 km true absorption was found at λ < 0.55 μm with the (1 ? ω0) maximum at H ≈ 15 km. The wavelength and height dependence of the absorption coefficient are compatible with the assumption that sulfur with a mixing ratio ~2 × 10?8 normalized to S2 molecules is the absorber. The upper limits of the mixing ratio for Cl2, Br2, and NO2 are 4 × 10?8, 2 × 10?11, and 4 × 10?10, respectively. The CO2 and H2O bands are confidently identified in the observed spectra. The mean value of the H2O mixing ratio is 3 × 10?5 < FH2O < 10?4 in the undercloud atmosphere. The H2O mixing ratio evidently varies with height. The most probable profile is characterized by a gradual increase from FH2O = 2 × 10?5 near the surface to a 10 to 20 times higher value in the clouds.  相似文献   

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