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1.
The possible cosmological variation of the proton-to-electron mass ratio μ = m p/m e was estimated by measuring the H2 wavelengths in the spectra of distant quasars. We analyze high-resolution (FWHM≈7 km s?1) spectra of the two damped Lyman-α systems at redshifts z abs=2.3377 and 3.0249 observed in the spectra of the quasars Q 1232+082 and Q 0347?382, respectively. Our analysis yielded the most conservative estimate for the possible variation of μ in the past ～ 10 Gyr, Δμ/μ = (5.7 ± 3.8) × 10?5. Since the significance of this result does not exceed 1.5σ, further observations are needed to increase the statistical significance. This is the most stringent limit on the possible cosmological variation of μ to date.  相似文献   

2.
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   

3.
A concise explanation of studies on distortion of space-time dimension is briefly introduced. Second we obtain the limits (i.e., bounded values) of the dimensionless chemical potential μ, the Sunyaev–Zeldovich (SZ) effect y and distortion of the space-dimension ε by Monte Carlo (MC) analysis of the parameter set (T, d=3+ε, μ, and y) in cosmic microwave data assuming that the SZ effect is positive (y>0). In this analysis, the magnitude of the space-dimension d with distortion of the space-dimension ε is defined by d=3+ε. The limits of μ and y are determined as |μ|<9×10?5 (2σ) (μ=(?3.9±2.6)×10?5 (σ)), |y|<5×10?6 (2σ) (y=(2.0±1.4)×10?6 (σ)), while the distortion of the space-dimension is |ε|<6×10?5 (2σ) (ε=(?0.78±2.50)×10?5 (σ)). The magnitudes of these three estimated limits are ordered as . The estimated limit of |y|<5×10?6 appears to be related to re-ionization processes occurring at redshift z ri ～10. We also present data analysis assuming a relativistic SZ effect.  相似文献   

4.
This paper presents a new family of interior solutions of Einstein–Maxwell field equations in general relativity for a static spherically symmetric distribution of a charged perfect fluid with a particular form of charge distribution. This solution gives us wide range of parameter, K, for which the solution is well behaved hence, suitable for modeling of superdense star. For this solution the gravitational mass of a star is maximized with all degree of suitability by assuming the surface density equal to normal nuclear density, ρ nm=2.5×1017 kg?m?3. By this model we obtain the mass of the Crab pulsar, M Crab, 1.36M ⊙ and radius 13.21 km, constraining the moment of inertia >?1.61×1038 kg?m2 for the conservative estimate of Crab nebula mass 2M ⊙. And M Crab=1.96M ⊙ with radius R Crab=14.38 km constraining the moment of inertia >?3.04×1038 kg?m2 for the newest estimate of Crab nebula mass, 4.6M ⊙. These results are quite well in agreement with the possible values of mass and radius of Crab pulsar. Besides this, our model yields moments of inertia for PSR J0737-3039A and PSR J0737-3039B, I A =1.4285×1038 kg?m2 and I B =1.3647×1038 kg?m2 respectively. It has been observed that under well behaved conditions this class of solutions gives us the overall maximum gravitational mass of super dense object, M G(max)=4.7487M ⊙ with radius $R_{M_{\max}}=15.24~\mathrm{km}$ , surface redshift 0.9878, charge 7.47×1020 C, and central density 4.31ρ nm.  相似文献   

5.
The model of a presupernova’s carbon-oxygen (C-O) core with an initial mass of 1.33 M ⊙, an initial carbon abundance X C (0) =0.27, and a mean rate of increase in mass of 5 × 10?7 M ⊙ yr?1 through accretion in a binary system evolved from the central density and temperature ρc=109 g cm?3 and T c=2.05 × 108K, respectively, by forming a convective core and its subsequent expansion to an explosive fuel ignition at the center. The evolution and explosion equations included only the carbon burning reaction 12C+12C with energy release corresponding to the complete conversion of carbon and oxygen (at the same rate as that of carbon) into 56Ni. The ratio of mixing length to convection-zone size αc was chosen as the parameter. Although the model assumptions were crude, we obtained an acceptable (for the theory of supernovae) pattern of explosion with a strong dependence of its duration on αc. In our calculations with sufficiently large values of this parameter, αc=4.0 × 10?3 and 3.0×10?3, fuel burned in the regime of prompt detonation. In the range 2.0×10?3≥αc≥3.0×10?4, there was initially a deflagration with the generation of model pulsations whose amplitude gradually increased. Eventually, the detonation regime of burning arose, which was triggered from the model surface layers (with m ? 1.33 M ⊙) and propagated deep into the model up to the deflagration front. The generation of model pulsations and the formation of a detonation front are described in detail for αc=1.0 × 10?3.  相似文献   

6.
We present some families of horseshoe periodic orbits in the general planar three-body problem for the case of two equal masses. The considered system is a symmetric version of the one formed by Saturn, Janus and Epimetheus. We use a mass ratio equal to 35×10−5, corresponding to 105 times the Saturn-Janus mass parameter of the restricted case; for this mass ratio the satellites have a significantly bigger influence on the planet than in the classical Saturn, Janus and Epimetheus system. To obtain periodic orbits, we search those horseshoe orbits passing through two reversible configurations. A particular kind of periodic orbits where the minor bodies follow the same path is discussed.  相似文献   

7.
Multiaperture K photometry and 2.0- to 2.5-μm spectrophotometry of Uranus and its ring system are presented. The photometric results are used, together with a previously published measurement, to set limits on the geometric albedos of Uranus and the rings at ～2.2 μm: (0.74 ± 0.02) × 10(su?4) ≤ pK (Uranus) ≤ (1.5 ± 0.3) × 10?4, and (2.7 ± 0.6) × 10?2 ≤ pK (rings) ≤ (3.4 ± 0.1) × 10?2. Reflectance spectra of Uranus and Uranus plus rings show features in the planet's spectrum which are attributed to gaseous CH4 absorption, and a 2.20-μm feature in the combined spectrum which may be due to the rings. This feature is tentatively identified with either the 2.26-μm absorption feature of NH3 frost, or the 2.2-μm OH band exhibited by certain silicate minerals. The results of JHK photometry of Uranus' satellite, Ariel (U1), indicate that the infrared colors of this object are very similar to those of the satellites U2, U3, and U4.  相似文献   

8.
We consider the planar restricted three-body problem and the collinear equilibrium point L 3, as an example of a center × saddle equilibrium point in a Hamiltonian with two degrees of freedom. We explore numerically the existence of symmetric and non-symmetric homoclinic orbits to L 3, when varying the mass parameter μ. Concerning the symmetric homoclinic orbits (SHO), we study the multi-round, m-round, SHO for m ≥ 2. More precisely, given a transversal value of μ for which there is a 1-round SHO, say μ 1, we show that for any m ≥ 2, there are countable sets of values of μ, tending to μ 1, corresponding to m-round SHO. Some comments on related analytical results are also made.  相似文献   

9.
Based on a one-dimensional hydrodynamic model, we investigate carbon burning in a thermonuclear type-Ia supernova in the approximation of unsteady convection. The relatively broad range of convective parameters, 1×10?3≤αc≤2×10?3, in which delayed detonation from the edge takes place was found to be preserved only for cases with a low boundary temperature at the presupernova stage, T b (PS) = 6.4 × 106 K, and with a high envelope mass, mex ? 2 × 10?3M⊙. In cases with a more realistic temperature, T b (PS) = 2 × 108 K, which corresponds to helium burning in the shell source, and with a lower mass mex, delayed detonation from the edge takes place only at αc = 2 × 10?3, while at αc = 1 × 10?3, numerous model pulsations occur during t?500 s. Artificial viscosity is shown to give a determining contribution to the increase in entropy in outer model shells, which is caused by the generation of weak shock waves during pulsations. We also show that the entropies calculated by two independent methods are equal.  相似文献   

10.
We studied the intermediate polar TVCol during and after its flare in November 1982 observed in the ultraviolet range with the International Ultraviolet Explorer. Two spectra revealing the variations of emission lines at different times are presented. We have estimated a new value of the reddening from the 2200 Å absorption feature, E (B ? V ) = 0.12 ± 0.02, and calculated the line fluxes of C IV and He II emission lines produced in the outer accretion disk. The average ultraviolet luminosity of emitting region during and after the flare is approximately 4 × 1032 erg s?1 and 9 × 1030 erg s?1, the corresponding average mass accretion rate is nearly 3 × 1015 erg s?1 (4.76 × 10?11M⊙ yr?1) and 5 × 1013 erg s?1 (7.93 × 10?13M⊙ yr?1), and the average temperature of the emitting region during and after flare is estimated to be of about 3.5 × 103 K and 2 × 103 K. We attribute this flare to a sudden increase in the mass accretion rate leading to the outburst activity.  相似文献   

11.
Previous studies based on radio scintillation measurements of the atmosphere of Venus have identified two regions of small-scale temperature fluctuations located in the vicinity of 45 and 60 km. A global study of the fluctuations near 60 km, which are consistent with wind-shear-generated turbulence, was conducted using the Pioneer Venus measurements. The structure constants of refractive index fluctuations cn2 and temperature fluctuations cT2 increase poleward, peak near 70° latitude, and decrease over the pole; cn2 varies from 2 × 10?15 to 1.5 × 10?14m23 and cT2 from 4 × 10?3 to 7 × 10?2°K2m?23. These results indicate greater turbulent activity at the higher latitudes. In the region near 45 km the refractive index fluctuations and the corresponding temperature fluctuations are substantially lower. Based on the analysis of one representative occultation measurement, cn2 = 2 × 10?16m?23and cT2 = 7.3 × 10?4°K2m?23 in the 45-km region. The fluctuations in this region also appear to be consistent with wind-shear-generated turbulence. The turbulence level is considerably weaker than that at 60 km; the energy dissipation rate ε is 4.9 × 10?5m2sec?3 and the small-scale eddy diffusion coefficient K is 2 × 103 cm2 sec?1.  相似文献   

12.
The impact light flash produced by electrostatically accelerated iron particles with diameters meters ranging from 5 to 0.05 μm and velocities lying between 1 km/sec and 30 km/sec has been investigated by means of photomultipliers. As target materials mainly gold and tungsten were used. The pulse of the multiplier was registered directly and after electronic integration. The pulse height of the multiplier signal, the amplitude of the integrated signal as well as its rise time were found to be unique functions of the mass and velocity of the impacting particle. For the pulse height of the differential signal the relation I = c1 × m1.25 × v5 was obtained, and for the integrated signal the relation I = c2 × m1.25 × v3.8, with only c1 and C2 depending on the target material. The rise time of the integrated signal follows the relation T = 2.2 × 102 × v?0.4 using gold as target, and in the case of tungsten material follows the relation T = 9.8 × 102 × v?1.2, where v is expressed in km/sec and T in μsec. Using the spectral distribution of the light intensity, measured by means of calibrated photomultipliers, the total amount of light energy emitted in the visible range could be calculated. As a result we obtained that for v = 4 km/sec and m = 10?11 g about 3 × 10?4 of the kinetic energy of the particle was converted into light energy. The variation of the impact flash intensity with the target material and the measured spectral distribution allowed the temperature of the crater after the impact to be estimated as between 2000 and 3000 K.  相似文献   

13.
The radio radii of the Sun at wavelengths of 5, 10.7, 12, and 95 cm have been determined from eclipse observations as R5 ?? (1.0 ± 0.015)R ??, R 10,12 = (1.05 ± 0.003)R ??, and R 95 = (1.2 ± 0.02)R ??. The bright-ness temperatures of quiet solar disk areas at these wavelengths have turned out to be Td 5 = (22 ± 2) × 103, Td 10 = (44 ± 3) × 103, Td 12 = (47 ± 3) × 103, and Td 95 = (1000 ± 30) × 103 K. There were local sources of radio emission with angular sizes from 1.9 to 2.4 arcmin and brightness temperatures from 80 × 103 to 1.75 × 106 K above sunspot groups at short wavelengths of 5, 10.7, and 12 cm. The radio flux from the local sources at 95 cm turned out to be below the detection threshold of 1.0 × 10?22 W m?2 Hz?1. Comparison of the values obtained with the results of observations of another eclipse on August 1, 2008, occurred at the epoch of minimum of the 11-year solar cycle has shown that the radio radius of the Sun at 10.7 and 12 cm increased from 1.016 R ?? to 1.05 ± 0.003R ??, the height of the emitting layer at these wavelengths moved from 11 × 103 km to (30 ± 7) × 103 K, and the brightness temperature of the quiet Sun rose from (35.8 ± 0.4) × 103 K to (44 ± 3) × 103 K at 10.7 cm and from (37.3 ± 0.4) × 103 K to (47 ± 3) × 103 K at 12 cm. Consequently, the parameters of the solar atmosphere changed noticeably in 2 years in connection with the beginning of the new solar cycle 24. The almost complete absence of local sources at the longest wavelength of 95 cm suggests that the magnetic fields of the sunspot groups on January 4, 2011, were weak and did not penetrate to the height from where their emission could originate. If this property is inherent in most sunspot groups of cycle 24, then it can be responsible for its low flare activity.  相似文献   

14.
V.S. Safronov  E.L. Ruskol 《Icarus》1982,49(2):284-296
A two-stage growth of the giant planets, Jupiter and Saturn, is considered, which is different from the model of contraction of large gaseous protoplanets. In the first stage, within a time of ～3 × 107 years in Jupiter's zone and ～2 × 108 years in Saturn's zone, a nucleus forms from condensed (solid) material having the mass, ～1028 g, necessary for the beginning of acceleration. The second stage may gravitating body, and a relatively slow accretion begins until the mass of the planet reaches ～10 m⊕. Then a rapid accretion begins with the critical radius less than the radius of the Hill lobe, so that the classical formulae for the rate of accretion may be applied. At a mass m > m1 ≈ 50 m⊕ accretion proceeds slower than it would according to these formulae. When the planet sweeps out all the gas from its nearest zone of feeding (m = m2 ≈ 130 m⊕), the width of the exhausted zone being ～built13 of the whole zone of the planet) growth is provided the slow diffusion of gas from the rest of the zone (time scale increases to 105?106 years and more). The process is terminated by the dissipation of the remnants of gas. In Saturn's zone m1 > m2 ≈ 30 m⊕. The initial mass of the gas in Jupiter's zone is estimated. Before the beginning of the rapid accretion about 90% of the gas should have been lost from the solar system, and in the planet's zone less than two Jupiter masses remain. The highest temperature of Jupiter's surface, ≈5000°K, is reached at the stage of rapid accretion, m < 100 m⊕, when the luminosity of the planet reaches 3 × 10?3 L⊙. This favors an effective heating of the inner parts of the accretionary disk and the dissipation of gas from the disk. The accretion of Saturn produced a temperature rise up to 2000?2400° K (at m ≈ 20?25 m⊕) and a luminosity up to 10?4 L⊙.  相似文献   

15.
This study analyzes the evolution of 2 × 105 orbits with initial parameters corresponding to the orbits of comets of the Oort cloud under the action of planetary, galactic, and stellar perturbations over 2 × 109 years. The dynamical evolution of comets of the outer (orbital semimajor axes a > 104 AU) and inner (5 × 103 < a (AU) < 104) parts of the comet cloud is analyzed separately. The estimates of the flux of “new” and long-period comets for all perihelion distances q in the planetary region are reported. The flux of comets with a > 104 AU in the interval 15 AU < q < 31 AU is several times higher than the flux of comets in the region q < 15 AU. We point out the increased concentration of the perihelia of orbits of comets from the outer cloud, which have passed several times through the planetary system, in the Saturn-Uranus region. The maxima in the distribution of the perihelia of the orbits of comets of the inner Oort cloud are located in the Uranus-Neptune region. “New” comets moving in orbits with a < 2 × 104 AU and arriving at the outside of the planetary system (q > 25 AU) subsequently have a greater number of returns to the region q < 35 AU. The perihelia of the orbits of these comets gradually drift toward the interior of the Solar System and accumulate beyond the orbit of Saturn. The distribution of the perihelia of long-period comets beyond the orbit of Saturn exhibits a peak. We discuss the problem of replenishing the outer Oort cloud by comets from the inner part and their subsequent dynamical evolution. The annual rate of passages of comets of the inner cloud, which replenish the outer cloud, in the region q < 1 AU in orbits with a > 104 AU (～ 5.0 × 10?14 yr?1) is one order of magnitude lower than the rate of passage of comets from the outer Oort cloud (～ 9.1 × 10?13 yr?1).  相似文献   

16.
The results of JHKLM photometry for Nova Delphini 2013 obtained in the first sixty days after its outburst are analyzed. Analysis of the energy distribution in a wide spectral range (0.36–5 µm) has shown that the source mimics the emission of normal supergiants of spectral types B5 and A0 for two dates near its optical brightness maximum, August 15.94 UT and August 16.86 UT, respectively. The distance to the nova has been estimated to be D ≈ 3 kpc. For these dates, the following parameters have been estimated: the source’s bolometric fluxes ～9 × 10?7 and ～7.2 × 10?7 erg s?1 cm?2, luminosities L ≈ 2.5 × 105 L ⊙ and ≈2 × 105 L ⊙, and radii R ≈ 6.3 × 1012 and ≈1.2 × 1013 cm. The nova’s expansion velocity near its optical brightness maximum was ～700 km s?1. An infrared (IR) excess associated with the formation of a dust shell is shown to have appeared in the energy distribution one month after the optical brightness maximum. The parameters of the dust component have been estimated for two dates of observations, JD2456557.28 (September 21, 2013) and JD2456577.18 (October 11, 2013). For these dates, the dust shell parameters have been estimated: the color temperatures ≈1500 and ≈1200 K, radii ≈6.5 × 1013 and 1.7 × 1014 cm, luminosities ～4 × 103 L ⊙ and ～1.1 × 104 L ⊙, and the dust mass ～1.6 × 1024 and ～1025 g. The total mass of the material ejected in twenty days (gas + dust) could reach ～1.1 × 10?6 M ⊙. The rate of dust supply to the nova shell was ～8 × 10?8 M ⊙ yr?1. The expansion velocity of the dust shell was about 600 km s?1.  相似文献   

17.
Simultaneous measurements of NO and NO2 in the stratosphere leading to an NOx determination have been performed by means of i.r. absorption spectrometry using the Sun as a source in the 5·2 μm band of NO and in the 6·2 μm band of NO2. The observed abundance of NOP peaks at 26 km where it is equal to (4·2 ± 1) × 109 cm?3. The volume mixing ratio of NOp was observed to vary from 1·3 × 10?9 at 20 km to 1·3 × 10?8 at 34 km.  相似文献   

18.
A periodic orbit of the restricted circular three-body problem, selected arbitrarily, is used to generate a family of periodic motions in the general three-body problem in a rotating frame of reference, by varying the massm 3 of the third body. This family is continued numerically up to a maximum value of the mass of the originally small body, which corresponds to a mass ratiom 1:m 2:m 3?5:5:3. From that point on the family continues for decreasing massesm 3 until this mass becomes again equal to zero. It turns out that this final orbit of the family is a periodic orbit of the elliptic restricted three body problem. These results indicate clearly that families of periodic motions of the three-body problem exist for fixed values of the three masses, since this continuation can be applied to all members of a family of periodic orbits of the restricted three-body problem. It is also indicated that the periodic orbits of the circular restricted problem can be linked with the periodic orbits of the elliptic three-body problem through periodic orbits of the general three-body problem.  相似文献   

19.
The rates and altitudes for the dissociation of atmospheric constituents of Titan are calculated for solar UV, solar wind protons, interplanetary electrons, Saturn magnetospheric particles, and cosmic rays. The resulting integrated synthesis rates of organic products range from 102–103 g cm?2 over 4.5 × 109 years for high-energy particle sources to 1.3 × 104 g cm?2 for UV at λ < 1550 A?, and to 5.0 × 105 g cm?2 if λ > 1550 A? (acting primarily on C2H2, C2H4, and C4H2) is included. The production rate curves show no localized maxima corresponding to observed altitudes of Titan's hazes and clouds. For simple to moderately complex organic gases in the Titanian atmosphere, condensation occurs below the top of the main cloud deck at 2825 km. Such condensates comprise the principal cloud mass, with molecules of greater complexity condensing at higher altitudes. The scattering optical depths of the condensates of molecules produced in the Titanian mesosphere are as great as ～ 102/(particulate radius, μm) if column densities of condensed and gas phases are comparable. Visible condensation hazes of more complex organic compounds may occur at altitudes up to ～ 3060 km provided only that the abundance of organic products declines with molecular mass no faster than laboratory experiments indicate. Typical organics condensing at 2900 km have molecular masses = 100–150 Da. At current rates of production the integrated depth of precipitated organic liquids, ices, and tholins produced over 4.5 × 109 years ranges from a minimum ～ 100 m to kilometers if UV at λ > 1550 A? is important. The organic nitrogen content of this layer is expected to be ～ 10?1?10?3 by mass.  相似文献   

20.
Earlier, under certain simplifying assumptions, on the basis of the General Theory of Relativity, it has been concluded by many authors that when the radius of a gravitationally collapsing spherical object of massM reaches the critical value of the Scharzschild radiusR s=2GM/c 2, then, in a co-moving frame, the object collapses catastrophically to a point. However, in drawing this conclusion due consideration has not been given to the nuclear forces between the nucleons. In particular, the very strong ‘hard-core’ repulsive interaction between the nucleons which has the range ～0.4×10?13 cm has been totally ignored. On taking into account this ‘hard-core’ repulsive interaction, it is found that no spherical object of massM g can collapse to a volume of radius smaller thanR min=(1.68×10?6)M 1/3 cm or to a density larger than ρmax=5.0 × 1016 g cm?3. It has also been pointed out that objects of mass smaller thanM c～1.21×1033 g can not cross the Schwarzschild barrier and gravitationally collapse. The only course left to the objects of mass less thanM cis to reach the equilibrium as either a white dwarf or a neutron star.  相似文献   

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