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1.
Microorganisms sealed in KBr dises have an absorption spectrum over the 2.5–15 m waveband that shows thermal stability as they are heated in an inert atmosphere to temperatures of about 400°C. Microfossils tightly sealed within cavities in rocks could be endowed with similar properties of thermal stability. The observed absorption of interstellar material along the line of sight from the solar system to the galactic centre is remarkably similar to the spectrum of dry micro-organisms over the 3.15–3.7 m waveband.  相似文献   

2.
The ionization equilibrium of the Fe in the solar corona for a non-Maxwellian electron distribution with an enhanced number of particles in the high-energy tail is presented. A parametric form of the distribution function is used to demonstrate the changes in the ionization equilibrium with changes in the shape of the distribution. The results over the range of temperature 105 K T 108 K for different deviations of the distribution from a Maxwellian are given in tabular form. The results can be used for specific applications in the solar corona, especially in the active corona, where deviations from the Maxwellian distribution can be significant.  相似文献   

3.
Radiometric measurement of the brightness temperature of the mean solar disk has been made in the wavelength range from 238 to 312 (42.1 cm-1 to 32.1 cm-1), using a Michelson interferometer of resolution 0.25 cm-1, carried on the NASA research aircraft at altitude 12.6 km. A mean temperature 4370 ± 260 K is obtained. The result is compared with other measurements of the solar minimum temperature and with the prediction of the BCA Model.The National Center for Atmospheric Research is sponsored by the National Science Foundation.  相似文献   

4.
A comparison is made of the observed intensity in the solar continuous spectrum with those predicted by some models. Arguments are given that the bend-off observed for < 0.6 is a real phenomenon, and due to a veiled line haze.  相似文献   

5.
We present an attempt for an extension of the modified Boltzmann model, which was introduced by Callebautet al. (1982) as an improvement of the polytropic models, to the case of chemically-heterogeneous stars in equilibrium, containing H and He, by proposing a density profile of the formp=C 1 T N exp (–H m(–*)/kT) +C 2 T N exp (–He m(–*)/kT. Analytical properties are derived and numerical as well as analytical arguments are presented for the conclusion that this hypothesis for a density profile imposes an almost constant chemical profile to the model as a whole, thereby making it in this form unsuited for the study of heterogeneous stars. A comparison is made with the former Boltzmann model in the homogeneous limit.  相似文献   

6.
A comparison is made between the stability criteria of Hill and that of Laplace to determine the stability of outer planetary orbits encircling binary stars. The restricted, analytically determined results of Hill's method by Szebehely and co-workers and the general, numerically integrated results of Laplace's method by Graziani and Black are compared for varying values of the mass parameter =m 2/(m 1+m 2). For 00.15, the closest orbit (lower limit of radius) an outer planet in a binary system can have and still remain stable is determined by Hill's stability criterion. For >0.15, the critical radius is determined by Laplace's stability criterion. It appears that the Graziani-Black stability criterion describes the critical orbit within a few percent for all values of .  相似文献   

7.
Based on far-infrared spectroscopy of a small sample of nearbyinfrared-bright and ultraluminous infrared galaxies (ULIRGs) with theISO Long Wavelength Spectrometer we find adramatic progression in ionic/atomic fine-structure emission line andmolecular/atomic absorption line characteristics in these galaxiesextending from strong [O III]52,88 m and [N III]57 m lineemission to detection of only faint [C II]158 m line emissionfrom gas in photodissociation regions in the ULIRGs. The molecularabsorption spectra show varying excitation as well, extending fromgalaxies in which the molecular population mainly occupies the groundstate to galaxies in which there is significant population in higherlevels. In the case of the prototypical ULIRG, the merger galaxy Arp220, the spectrum is dominated by absorption lines of OH, H2O, CH,and [O I]. Low [O III]88 m line flux relative to the integratedfar-infrared flux correlates with low excitation and does not appear tobe due to far-infrared extinction or to density effects. A progressiontoward soft radiation fields or very dusty H II regions may explainthese effects.  相似文献   

8.
The photometry of coronal colour negatives is carried out. The films were obtained at the March 7, 1970 and July 10, 1972 eclipses. A distribution of the coronal brightness in the red (635 nm), green (545 nm), and blue (455 nm) wavelength intervals up to distances of (6–7)R is deduced (Figure 1). Colour indexes of the corona (the emission ratio red/blue - C rb and green/blue - C gb) have been obtained. We assume C rb = C gb = 1 in the inner corona (2R ). The maximum of colour indexes of the 1970 corona are at the distances of about 4R (C rb 1.9 and C gb 1.7). A slight reddening within the limits of the errors was found in the 1972 corona.There is a correlation between colour indexes and diffuse external reinforcements (RED) brightness. The analysis of the results leads to the conclusion that RED consists of dust grains with radii 1 m. RED brightness is evaluated to be 4 × 10-10 B . There is 1 grain of dust in the elementary volume with cross section of 1 cm2 along the line of sight. The intensity of dust emission in wavelength interval 10 m deduced by the authors is approximately 1 W cm-2 s m–1. That is in agreement with Mankin et al. (1974) and Léna et al. (1974) observations. The whole dust mass of RED is 1% of the coronal gas mass contained within RED region. The dust grain number density is about 10-11 cm-3.Determinations of the colour of the solar corona have been made by a number of scientists (Tikhov, 1940, 1957; Allen, 1946; Blackwell, 1952; Michard, 1956; Sharonov, 1958; Nay et al., 1961). The corona colour was found to be somewhat redder than the Sun's. However this question is not finally settled to date.  相似文献   

9.
During the total solar eclipse of 11 June, 1983, an imaging dual-channel Fabry-Pérot interferometer was used to obtain line profiles simultaneously in the green 5303 Å [Fe xiv] and the red 6374 Å [Fe x] coronal lines at various positions in the corona. Extensive microdensitometry followed by multi-Gaussian curve-fitting analysis has resulted in the determination of coronal temperatures and velocity separations between different pockets of coronal gas in the line of sight over a large extent of the corona. Fewer high temperature zones are to be found in the corona of 1983 compared with our similar green-line measurements of the solar maximum corona of 1980. The data are consistent with a temperature maximum occurring at 1.2 R , as found at the 1980 eclipse, but our new data are insufficient to observe farther out than this radius and so determine the position of a maximum. The velocity field in the corona at the 1983 eclipse is less structured compared with that at the 1980 eclipse and is mainly confined to the zone 20–30km s–1.  相似文献   

10.
To explain the scattering of sunlight observed from theF-corona and from the zodiac, the scattering particles must have radii of order 15 m, and must have an imaginary component of the refractive index that requires the presence of from 5 to 10% of free carbon. The particles, therefore, have a composition very like the material of C 1 carbonaceous chondrites and like extraterrestrial particles which have been recovered from the high atmosphere.Such particles absorb sunlight, the absorbed solar energy being reradiated in the infrared with a close approximation to black-body emission, even as far into the infrared as 100 m, a deduction in good agreement with recently published observations from the IRAS satellite.The IRAS observations at high ecliptic latitudes require similar particles to be present in large quantity in the interstellar medium, 106 solar masses or more of them. The presence of such a quantity of material with properties very like the material of the C 1 carbonaceous chondrites is a remarkable outcome of the IRAS observations and is likely to have profound implications in many directions.  相似文献   

11.
Infrared continuum observations of the Sun at wavelengths between 10 and 30 show a nonisothermal response of the upper photosphere to compression waves associated with the five-minute oscillations. Observations were made with four broad-band filters with effective transmission wavelengths between 10 and 26 and with a 10 aperture. Further observations at submillimeter wavelengths with a 2 aperture did not resolve oscillatory fluctuations of five-minute period.Comparisons with velocity field data of Howard (1976) suggest that the relaxation time of the photosphere exceeds (300/2) seconds at the height of formation of the 26 continuum (5000Å 10-2). The photosphere reponds to 3 mHz oscillatory motion with considerably less compression than expected for simple acoustic modes in an adiabatically responsive atmosphere, confirming the evanescent character of the five-minute oscillations.  相似文献   

12.
A low-noise photoelectric scan which includes the predicted position of the Cli transition 4s 4 P 5/2-4 p 4 D 0 7/2 provides inconclusive evidence for the presence of the line in the solar photospheric spectrum. An upper limit logN(Cl) 5.5 is derived. It is pointed out that the fundamental vibration rotation band of HC1 at 3.3 should be detectable in the sunspot spectrum unless logN(Cl) < 4.6. Sunspot spectra may also provide the isotopic abundance ratio N(Cl35)/N(Cl37).A new derivation of the chlorine abundance for the Orion nebula is presented: logN(Cl) 5.8. It is suggested that a cosmic abundance logN(Cl) = 5.5 to 5.8 be adopted.Operated by the Association of Universities for Research in Astronomy Inc., under contract with the National Science Foundation.  相似文献   

13.
Kumar  Brajesh  Jain  Rajmal  Tripathy  S.C.  Vats  Hari Om  Deshpande  M.R. 《Solar physics》2000,191(2):293-307
A time series of GONG Dopplergrams for the period 10–14 May 1997 from Udaipur and Big Bear sites has been used to measure the velocity fluctuations in a sunspot (NOAA active region 8038) and quiet photosphere simultaneously. We observe that the power of pre-dominant p mode is reduced in the sunspot as compared to quiet photosphere by 39–52% depending on the location of the sunspot region on the solar disk. We also observe a relative peak frequency deviation of p modes in the sunspot, of the order of 80–310 Hz, which shows a linear dependence on the magnetic field gradient in the active region. The maximum frequency deviation of 310 Hz on 12 May appears to be an influence of a long-duration solar flare that occurred in this active region. We interpret this relative peak frequency deviation as either due to power re-distribution of p modes in the sunspot or a consequence of frequency modulation of these modes along the magnetic flux tubes due to rapidly varying magnetic field structure.  相似文献   

14.
A survey of the infrared coronal spectrum between 1 and 3 was made from a high altitude aircraft during the 7 March, 1970, solar eclipse. The observations were made with a Fourier transform spectrometer and were confined to the outer chromosphere and inner corona. In addition to well known chromospheric lines of Hi and Hei, nine additional lines were seen. Evidence is presented for the tentative assignment of these lines to forbidden transitions in highly ionized atoms of magnesium, aluminum, silicon, sulphur, and chromium.  相似文献   

15.
Existing models of the solar atmosphere predict a limb brightening in the far infrared wavelengths. At shorter wavelengths this effect is confined to the extreme limb but at 25 it extends inward from the limb to cos = 0.3. Observations of I()/I(1.0) were made with the McMath Solar Telescope through atmospheric windows at 10.4, 17.9, 20.4, and 24.2 microns, respectively. The measurements, after having been smoothed, are compared with the theoretical predictions taking into account the diffraction pattern of the telescope. The expected brightening does not appear.Kitt Peak National Observatory Contribution No. 260. - Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.Presently at Kitt Peak National Observatory, Tucson, Ariz., U.S.A.  相似文献   

16.
A discussion of a program for the computation of coronal emission line polarization is presented. The starting point is a general formulation of the scattering function for magnetic dipole transitions between any two total angular momentum levels, J J, J ± 1. Illustration of the behavior of the scattering function for different transitions is given. The integration of the scattering function over the solar disk and along the line of sight accounting for arbitrary distribution of magnetic fields as well as an inhomogeneous temperature and density structure of the corona is considered next.Sample results are presented for the numerical computation of the angle of maximum polarization and the degree of maximum polarization to be expected from idealized magnetic field configurations such as radial and dipole. A computation is included for a realistic field configuration predicted to exist at the time of the 1966 eclipse. The magnetic field input to the scattering calculation is based upon the potential field extension of photospheric magnetic fields. It is the purpose of the sample calculations to demonstrate how the measurement of emission polarization measurements can be interpreted in terms of the direction of coronal magnetic fields. Factors which lend ambiguity to such interpreations are clearly illustrated from the examples. These include the Hanle-effect depolarization and the depolarization at the Van Vleck angle.The National Center for Atmospheric Research is sponsored by the National Science Foundation.  相似文献   

17.
Results of families of periodic orbits in the elliptic restricted problem are shown. They are calculated for the mass ratios =0.5 and =0.1 for the primary bodies and for different values of the eccentricity of the orbit of the primaries which is the second parameter. The case =0.5 is also a good model for planetary orbits in binaries. Finally we show detailed stability diagrams and give results according to the stability classification of Contopoulos.  相似文献   

18.
We have obtained low noise (S/N > 103), high spectral resolution (/ 10 6) observations of two pure rotation transitions of OH from the solar photosphere. The observations were obtained using the technique of optically null-balanced infrared heterodyne spectroscopy, and consist of center-to-limb line profiles of a = 1 and a = 0 transition near 12 m. These lines should be formed in local thermodynamic equilibrium (LTE), and are diagnostics of the thermal structure of the upper photosphere. We find that the = 0R22(24.5)e line strengthens at the solar limb, in contradiction to the predictions of current one-dimensional photospheric models. Our data for this line support a two-dimensional model in which horizontal thermal fluctuations of order ±800 K occur in the region 5000 10–3–10–2. This thermal bifurcation may be maintained by the presence of magnetic flux tubes, and may be related to the solar limb extensions observed in the 30–200 m region.Observations of the = 1R11(29.5)f line, at 885.643 cm–1, show that it is anomalously weak in the photospheric spectrum. We argue that the source function in the core of this line has been substantially increased by interaction with the 9j-7i transition of Mgi at 885.524 cm–1, which is itself too weak to appear in the disk center spectrum.Visiting Astronomer, Kitt Peak National Observatory, which is operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation.  相似文献   

19.
A largely numerical study was made of families of three-dimensional, periodic, halo orbits near the collinear libration points in the restricted three-body problem. Families extend from each of the libration points to the nearest primary. They appear to exist for all values of the mass ratio , from 0 to 1. More importantly, most of the families contain a range of stable orbits. Only near L1, the libration point between the two primaries, are there no stable orbits for certain values of . In that case the stable range decreases with increasing , until it disappears at =0.0573. Near the other libration points, stable orbits exist for all mass ratios investigated between 0 and 1. In addition, the orbits increase in size with increasing .  相似文献   

20.
Stenflo  J. O. 《Solar physics》1974,37(1):31-42
The resonance polarization in Ca i 4226.73 has been measured close to the solar limb for three values of = cos. The polarization has maxima in the wings at about –500 and + 400 mÅ from the line center, the plane of polarization (electric vector) being parallel to the solar limb. The blue wing is more polarized than the red wing, contrary to earlier results of Brückner (1963). Local minima in the polarization curves occur at the position of blends. The polarization in the wings increases rapidly with decreasing . At = 0.15 the maximum polarization in the blue wing is about 2.4%.The observations are in good qualitative agreement with the recent theory of Dumont et al. (1973), but the observed polarization degrees are significantly smaller than the computed values. This may be explained by the inadequate formula for van der Waals broadening used in the theoretical calculations. Much of the discrepancies between observed and computed values disappear if the recent value of Lites (1974) for the collisional damping constant is used. Further improvements in theory and observation are discussed.  相似文献   

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