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1.
Aert Schadee 《Solar physics》1970,15(2):345-348
There is no evidence for the C2(0,1) band in an investigated sunspot spectrum. Upper limits are given for the band intensity.  相似文献   

2.
Douglas B. Nash 《Icarus》1983,54(3):511-523
The role of adsorbed SO2 on Io's surface particles in producing the observed spectral absorption band near 4 μm in Io's reflectance spectrum is explored. Calculations show that a modest 50% monolayer coating of adsorbed SO2 molecules on submicron grains of sulfur of alkali sulfide, assumed to make up Io's uppermost optical surface (“radialith”), will result in a ν1 + ν3 absorption band near 4 μm with depth ～30% below the adjacent continuum, consistent with the observed strength of the Io band. The precise wavelength position of the ν1 + ν3 band of SO2 in different phase states such as frost, ice, adsorbate, and gas are summarized from the experimental literature and compared with the available telescopic measurements of the Io band position. The results suggest that the 4-μm band in Io's full disk spectrum can best be explained by the presence on Io's surface of widespread SO2 in the form of adsorbate rather than ice or frost.  相似文献   

3.
The spectrum of Titan from 4800 to 11 000 Å has many CH4 absorption bands which cover a range of intensities of several orders of magnitude. Yet even the strongest of these bands in Titan's spectrum has considerable residual central intensity. Some investigators have concluded that these strong CH4 bands must be highly saturated, but recent laboratory measurements of the bands made at room temperature show that curve-of-growth saturation is very small. At the presumed low pressures and temperatures in Titan's atmosphere, we show that saturation is very dependent on the band model parameters. However, in either a simple reflecting layer model or in a homogeneous scattering model saturation cannot be the principal cause of the filling in of these strong CH4 bands if our best estimates of the band model parameters are correct. We find that an inhomogeneous scattering model atmosphere with fine “Axel dust” above most ot the CH4 gas is needed to fill in the band centers. The calculated spectrum of one particular model of this class is compared to observations of Titan. Our essential conclusion is that Titan does have most of its scattering particles above most of the CH4 gas which has an abundance of at least 2 km-am. This large abundance of CH4 is necessary to produce the 6420-Å feature recently discovered in Titan's spectrum.  相似文献   

4.
Observations of the 4-μm SO2 band on Jupiter's satellite Io and laboratory measurements of SO2 frost are presented. The observations confirm the existence of a large longitudinal variation in band strength but show no evidence of temporal changes. Comparison of the band position and shape in Io's spectrum with those in the laboratory frost's suggests that the bulk of the absorption on Io is due to frost, not adsorbed gas. The derived SO2 coverage is large enough to require that SO2 be present in most terrain types on Io and not just in the white plains unit. To reconcile the infrared observations that indicate large amounts of SO2 with the ultraviolet observations of Voyager and IUE that show little, the SO2 must be mixed intimately with the sulfur (or other material) so that at each wavelength the darker component dominates the spectrum.  相似文献   

5.
The expected equivalent widths of individual rotational lines of the most intense Q 2 branch of the 0-0 band of the A 2-X2i; system of S32H and S34H have been calculated in the umbral spectrum for five disk positions using Zwaan's (1974) sunspot model. Percentage abundance of S34 in the terrestrial case has been considered valid in our calculations.Strong lines of S32H and S34H of the A-X band system should be detectable in the sunspot spectrum. The molecule SH may play a possible role as a major opacity source in the ultraviolet spectrum of sunspots along with the molecule OH in the upper layers (up to 0.5m = 1.0) wherefrom most of the continuum arises. Study of this molecule in the umbral spectrum may also provide the solar isotopic abundance ratio N(S32)/N(S34).  相似文献   

6.
With the aim of investigating the resonance system of NO, equivalent width calculations have been made for the 213.575 nm, Q 1(31.5) line of the 1–0 band of -system of NO for the photospheric HSRA model, and for the line 214.012 nm, Q 1(25.5) line of the same band system for Zwaan's (1974) sunspot model.Calculations show that -band system would not show up in the photospheric spectrum whereas a sunspot model yields an equivalent width of 72 mÅ suggesting that sunspots may provide relatively more favourable conditions for the detections of the resonance systems of some abundant molecules in the inaccessible ultraviolet region.  相似文献   

7.
We present the results of the preliminary study of the comet Hale-Bopp spectrum obtained April 17, 1997 by K. Churyumov and F. Mussayev with the help of the 1-meter Zeiss reflector and the echelle spectrometer (spectral resolutionλ/Δ λ ≈ 50000), CCD and the long slit, oriented along the radius-vector(“Sun-comet direction”). Energy distributions for three selected regions including the C3, C2 (0-0) and CN(Δ ν = 0) molecules emissions of the comet Hale-Bopp spectrum were built. The rotational lines of the CN(Δ ν = 0) band were identified. The nature of the high emission peak near λ 4020 Å in the C3 band is discussed. The presence of the cometary continuum of the nonsolar origin is assumed.  相似文献   

8.
Soft X-ray emission from the X-ray source Per X-1 was observed in the 0.4–2 keV energy interval from a rocket borne X-ray detector. Spectral analysis of the data indicates that in the 0.4–2 keV band the X-ray emission from Per X-1 can be fitted either with a power law of slope-(4.8±1.2) or a thermal bremsstrahlung spectrum with akT value of (0.26 ?0.08 +0.12 ) keV. Such a steep spectrum is inconsistent with the spectrum measured above 2 keV. The measured flux in 0.4–2 keV band corresponds to X-ray luminosity of 3×1045 ergs s?1 for Per X-1.  相似文献   

9.
We report observation and analysis of a high-resolution 2.87-3.54 μm spectrum of the southern temperate region of Saturn obtained with NIRSPEC at Keck II. The spectrum reveals absorption and emission lines of five molecular species as well as spectral features of haze particles. The ν2+ν3 band of CH3D is detected in absorption between 2.87 and 2.92 μm; and we derived from it a mixing ratio approximately consistent with the Infrared Space Observatory result. The ν3 band of C2H2 also is detected in absorption between 2.95 and 3.05 μm; analysis indicates a sudden drop in the C2H2 mixing ratio at 15 mbar (130 km above the 1 bar level), probably due to condensation in the low stratosphere. The presence of the ν3+ν9+ν11 band of C2H6 near 3.07 μm, first reported by Bjoraker et al. [Bjoraker, G.L., Larson, H.P., Fink, U., 1981. Astrophys. J. 248, 856-862], is confirmed, and a C2H6 condensation altitude of 10 mbar (140 km) in the low stratosphere is determined. We assign weak emission lines within the 3.3 μm band of CH4 to the ν7 band of C2H6, and derive a mixing ratio of 9±4×10−6 for this species. Most of the C2H6 3.3 μm line emission arises in the altitude range 460-620 km (at ∼μbar pressure levels), much higher than the 160-370 km range where the 12 μm thermal molecular line emission of this species arises. At 2.87-2.90 μm the major absorber is tropospheric PH3. The cloud level determined here and at 3.22-3.54 is 390-460 mbar (∼30 km), somewhat higher than found by Kim and Geballe [Kim, S.J., Geballe, T.R., 2005. Icarus 179, 449-458] from analysis of a low resolution spectrum. A broad absorption feature at 2.96 μm, which might be due to NH3 ice particles in saturnian clouds, is also present. The effect of a haze layer at about 125 km (∼12 mbar level) on the 3.20-3.54 μm spectrum, which was not apparent in the low resolution spectrum, is clearly evident in the high resolution data, and the spectral properties of the haze particles suggest that they are composed of hydrocarbons.  相似文献   

10.
《Planetary and Space Science》1987,35(8):1061-1066
The N2+ First Negative band profiles in the high-altitude sunlit aurora are modeled by solving a set of simultaneous coupled equations for the population and depopulation of the N2+ vibrational and rotational energy levels. Approximations due to computer processing time and the use of1-→A averaged solar flux resulted in the loss of the Swings effect, but otherwise the modeled spectra simulate the observations and the characteristic high rotational development quite closely. Comparisons with the well-known spectrum of the 3914 Å band in the sunlit auroral ray published by Hunten et al. (1959, Nature 183, 453) give the N2+ ion lifetime of ∼103 s and N2X rotational temperature of ∼600 K, and are consistent with the fluorescent excitation mechanism; this contradicts conclusions made some two decades ago. A sample auroral cusp spectrum is included to illustrate the effects of Rayleigh scattering of solar flux.  相似文献   

11.
The main bands of the Schüler system of ND4 and NH4 have been observed at high resolution. On the basis of these spectra, Watson, in a separate paper, has analysed the ND4 main band showing that it represents a2F2 → 2 A1 transition of a tetrahedral molecule. The observed wavenumber data for both ND4 and NH4 are presented; the latter have not yet been analysed. Isotopic bands for15ND4,14ND3H,14ND2H2,14NDH3 have also been obtained and as previously pointed out confirm the assumed carrier of the spectrum. The much weaker bands accompanying the main Schüler band on the short and long wavelength sides are photographed at medium resolution. The interpretation of these bands in terms of the vibrational levels of upper and lower states is briefly discussed.  相似文献   

12.
The new black hole candidate XTE J1817-330, discovered on 26 January 2006 with RXTE, was observed with XMM-Newton and INTEGRAL in February and March 2006, respectively. The X-ray spectrum is dominated by the thermal emission of the accretion disk in the soft band, with a low absorption column density (N H=1.77(±0.01)×1021 cm−2) and a maximum disk temperature kT max=0.68(±0.01) keV, plus a power law component, with the photon index decreasing from 2.66±0.02 to 1.98±0.07 between the two observations. Several interstellar absorption lines are detected in the X-ray spectrum, corresponding to O I, O II, O III, O VII and Fe XXIV. We constrain the distance to the system to be in the range 1–5 kpc.   相似文献   

13.
The HCN emission features near 3 μm recently detected by Geballe et al. (2003, Astrophys. J. 583, L39) are analyzed with a model for fluorescence of sunlight in the ν3 band of HCN. The emission spectrum is consistent with current knowledge of the atmospheric temperature profile and the HCN distribution inferred from millimeter-wave observations. The spectrum is insensitive to the abundance of HCN in the thermosphere and the thousand-fold enhancement relative to photochemical models suggested by Geballe et al. (2003, Astrophys. J. 583, L39) is not required to explain the observations. We find that the spectrum can be matched with temperatures from 130 to 200 K, with slightly better fits at high temperature, contrary to the temperature determination of 130±10 K of Geballe et al. (2003, Astrophys. J. 583, L39). The HCN emission spectrum is sensitive to the collisional de-excitation probability, P10, for the ν3 state and we determine a value of 10−5 with an accuracy of about a factor of two. Analysis of absorption lines in the C2H2ν3 band near 3 μm, detected in the same spectrum, indicate a C2H2 mole fraction near 0.01 μbar of 10−5 for P10=10−4. The derived mole fraction, however, is dependent upon the value adopted for P10 and lower values are required if P10 at Titan temperatures is less than its room temperature value.  相似文献   

14.
The 5ν1 absorption band of NH3 is displayed from 6418 to 6550 Å. The total band intensity has been measured: SB = 0.66 cm?1m?1amagat?1. Line intensities and self-broadening coefficients have been measured for some of the prominent lines. Our line intensities are in good agreement with those of Rank et al. (1966), but are about 2 times greater than those of Mason (1970). The spectrum displayed was obtained photoelectrically at a pressure of 0.061 atm, and shows many more lines than the spectrum obtained by McBride and Nicholls (1972a) at a pressure of 0.39 atm. Therefore, our new measurements can provide the basis for making a more complete rotational analysis than those of McBride and Nicholls (1972a).Since the total band absorption has previously been measured by others on moderate resolution photoelectric scans of the spectra of Jupiter and Saturn, we can use the band intensity to derive the NH3 abundance in the atmospheres of these two planets. The NH3 abundances in a single vertical path obtained by this method are about 10m amagat for Jupiter and 2m amagat for Saturn. These results are in agreement with previous results obtained from higher resolution photographic spectra.  相似文献   

15.
We have found that 0.8 MeV proton irradiation of crystalline H2O-ice results in temperature dependent amorphization. The H2O-ice's phase was determined using the near infrared spectrum from 1.0 μm (10,000 cm−1) to 2.5 μm (4000 cm−1). In crystalline H2O-ice, the 1.65-μm (6061 cm−1) band is strong while it is nearly absent in the amorphous spectrum [Schmitt, B., Quirico, E., Trotta, F., Grundy, W.M., 1998. In: Schmitt, B., de Bergh, C., Festou, M. (Eds.), Solar System Ices. Kluwer Academic, Norwell, MA, 1998, pp. 199-240]. In this experiment, at low temperatures (9, 25, and 40 K), irradiation of crystalline H2O-ice produced the amorphous H2O-ice's spectrum. However, at 50 K, some crystalline absorptions persisted after irradiation and at 70 and 100 K the crystalline spectrum showed only slight changes after irradiation. Our results agree with previous H2O-ice irradiation studies examining the crystalline peaks near 44 and 62 μm by Moore and Hudson [Moore, M.H., Hudson, R.L., 1992. Astrophys. J. 401, 353-360] and near 3.07 μm by Strazzulla et al. [Strazzulla, G., Baratta, G.A., Leto, G., Foti, G., 1992. Europhys. Lett. 18, 517-522] and by Leto and Baratta [Leto, G., Baratta, G.A., 2003. Astron. Astrophys. 397, 7-13]. We present a method of measuring band areas to quantify the phase and radiation dose of icy Solar System surfaces.  相似文献   

16.
L.G. Parcel  W.I. Beavers 《Icarus》1974,23(4):623-629
Preliminary results of a spectrum scanner study of Comet Kohoutek (1973f) are reported. Ratios of band sequence fluxes and their variations with solar distance have been determined for three sequences of C2, and two sequences of CN from observations obtained on eleven dates. The λ4050 feature of C3 was visible on two dates, and CH (λ4300) detectable once.  相似文献   

17.
Forty-seven well exposed photographic plates of Venus which show the spectrum of the carbon dioxide band at 7820Å were obtained at Table Mountain Observatory in September and October 1972. These spectra showed a semiregular four-day variation in the CO2 abundance over the disk of the planet (Young et al., 1974). We also find evidence for temporal variations in the rotational temperature of this band and temperature variations over the disk. The two quantities, CO2 abundance and temperature, do not show any obvious relationship; however, an increase in the temperature usually is accompanied by a decrease in the abundance of CO2. The average temperature, found from a curve-of-growth analysis assuming a constant CO2 line width, is 249±1.4K (one standard deviation). This temperature is noticeably higher than the rotational temperature of 242±2K found for this same band in 1967 (Schorn et al., 1969) and of 242±1.2K in 1968–1969 (Young et al., 1971).  相似文献   

18.
Sang J. Kim  John Caldwell 《Icarus》1982,52(3):473-482
The 8.6-μm emission feature of Titan's infrared spectrum was analyzed using the Voyager temperature-pressure profile. Although both C3H8 and CH3D have bands at that wavelength, we show that CH3D dominates the observed emission on Titan. We derived a CH3D/CH4 mixing ratio using this band and the strong CH4 band at 7.7 μm. The corresponding D/H ratio is 4.2?1.5+2 × 10?4, neglecting deuterium fractionation with other molecules. The main uncertainty in this value comes from the continuum emission characteristics. The D/H ratio is apparently significantly enhanced on Titan with respect to published values for Saturn.  相似文献   

19.
Some absorption features in the ultraviolet spectrum of Venus observed by the OAO-2 cannot be interpreted in terms of H2SO4. Carbon suboxide polymer has a yellow colour and absorption at 2000 Å. Fine graphite grains have an absorption band at about 2175 Å as is well known in the case of the interstellar extinction curves. A mixture of these substances which is inevitably formed in the Venus atmosphere by photochemical reactions is the best candidate for explaining the Venus absorption features in the ultraviolet.  相似文献   

20.
A critical analysis has been made of solar irradiance in the spectral region covering wavelengths from 100 nm upwards; the absorption characteristics of molecules of oxygen and ozone have been taken into account with a view to the direct application of the results to atmospheric photochemistry. The absorption of radiation by these molecules results in the photodissociation of both of them in the homosphere, and it also makes possible the penetration of solar radiation from the thermosphere, through the mesosphere and the stratosphere, down to the troposphere.Special attention has been given to each of the following spectral regions: Lyman-alpha radiation at 121.6 nm, the O2 Schumann-Runge continuum at wavelengths less than 175 nm, the O2 Schumann-Runge band system from 200 to 175 nm, and the O2 Herzberg continuum at 242.4 nm. For absorption by ozone, the solar spectrum has been analysed in the following regions: the Hartley band at wavelengths less than 310 nm, the Huggins bands at wavelengths above 310 nm and the visible Chappuis bands. Finally, for the photodissociation of O3, particular attention has been given to the transition region (300–320 nm) in which there is a change-over from the production of the excited atom O(1D) to that of the atom in its ground state O(3p).  相似文献   

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