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1.
Line profiles of Euii 4129.7 Å and Laii 4086.7 Å were observed photoelectrically and photographically in the photosphere and within sunspots and after correction were compared with calculated profiles. The observed large hyperfine structure broadening and isotope shift of 4129.7 Å confirm the Eu origin of this line and suggest a larger Eu abundance than that recently published by Grevesse and Blanquet (1969). The line profiles within the spot may be well represented by means of the spot model of Hénoux (1969), while older spot models are not able to do it. An abundance difference between spot and photosphere has not been observed.  相似文献   

2.
Suemoto  Z. 《Solar physics》1977,51(1):3-24
Profiles of the Ba ii 4554 resonance line and the Mg i 4571 intercombination line are presented, observed near the limb of the Sun. They are obtained from eclipse spectrograms with good spectroscopic resolution and an accurate height calibration. The reduction of the observations is described and detailed profiles are given for a range of viewing angles (1/cos = 4 – 22).  相似文献   

3.
Solar flare observations have been performed with the multichannel L.P.S.P. experiment on board OSO-8 NASA Satellite. Simultaneous H and K Caii, h and k Mgii, L and L Hi profiles have been recorded on the plage just before the flare, during the flare onset and relaxation phases. The different behaviour of line profiles and intensities during the flare is evidenced and indicates a downward propagation with relaxation times increasing from the upper part to the lower part of the chromosphere related to line formation processes. Using the H observed profile, an upper limit of 8 × 1013 cm-3 is derived for the electron density.  相似文献   

4.
This paper describes the results of comparing SERTS-3 images obtained in the transition region line of Heii 304 with chromospheric Hei 10830 absorption, with strong coronal lines of Mgix 368 , Fexv 284 and 417 , and Fexvi 335 and 31 , with H, with Caii 8542 , and with magnetograms in Fei 8688H. All of the images are illustrated, and the image reconstruction techniques used are described and evaluated. The high correlation of the Heii 304 and Hei 10830 images, originally found by Harvey and Sheeley (1977), is confirmed and is put on a quantitative basis. We find that the supergranulation network has greater contrast, and that filaments appear darker, in 10830 than in 304 . In active regions, the 304 line follows more closely the behavior of H and Caii 8542 than the 10830 line.  相似文献   

5.
Characteristics of the emission observed above the solar limb in four EUV lines, Sixii 499, Mgx 625, Neviii 770, and Ovi 1032 are discussed. The mean temperature of the corona derived from the ratios of the intensities of Sixii 499 and Mgx 625 is 1.8 million K. There do not appear to be significant temperature differences in regions with low EUV intensities and those with high EUV intensities, suggesting that the EUV emission from the lithium-like ions depends primarily on the integral of n e 2 along the line of sight.The EUV data are compared with K-coronameter measurements in order to yield new estimates of the abundances of Si, Mg, Ne and O relative to hydrogen. Within the uncertainties of the analysis, these coronal abundances are in agreement with the corresponding photospheric values.  相似文献   

6.
J. Staude 《Solar physics》1970,15(1):102-112
The strong temperature dependence of the line Fei 5250.2 has been studied by calculating line contours and magnetographic calibration curves for different spot models and the BCA. Line contours calculated for arbitrary depth dependence of the magnetic field vector show depolarization effects within the Zeeman components for transversal fields with variable direction and changes of the observed plane of polarization if anomalous dispersion is taken into account.The observed anomalous splitting of the -component may be interpreted best by suggesting discrete inhomogeneities of the magnetic field within sunspots.  相似文献   

7.
Spectroheliograms in the L Mg xii line and in the Mg xi resonance (R) 1s 21 S 0-1s2p 1 P 1 line, intercombination (I) 1s 21 S 0-1s2p 3 P 1,2, line, and the forbidden (F) 1s 21 S 0-1s2s 3 S 1 line, have been obtained.Two Bragg crystal spectrometers were used mounted with mechanical collimators to obtain a spatial resolution of 1 × 3. The apparatus was launched on a sounding rocket on July 2nd, 1971. A particularly thorough study was made of the brightest active region (MC 11402).Variations in the F to I Mg xi line intensity ratio from one point to another in the active region did not reveal the presence of high electron densities.The observed intensities of the Mg xi R line, Mg xii L line and Mg x 1s 22s 2 S 1/2-1s2p 1 P 2s × × 2 P11/2, 3/2 S line are not well explained by an isothermal model. Good agreement between computed and observed intensities is obtained using the non-isothermal model proposed here.  相似文献   

8.
We study the center-limb (CL) variation of the average profiles of four Ca i lines near 6500 and compare these observations with synthetic data obtained from several line formation models having different thermal structures, line parameters, LTE and non-LTE conditions, and micro and macroturbulence values, to assess the formation characteristics of our Ca i lines in the solar photosphere.Comparison of numerical results with observations indicates that non-LTE is indispensable to fit the CL variation of the central residual intensity for the line 6493, and anisotropic microturbulence is indispensable to improve the CL behavior of the equivalent widths for all lines. The Ca i line analysis favors a cool photospheric model, but this cannot be disentangled clearly from the effects of non-LTE and small-scale velocity fields on the grounds of the present line formation models.  相似文献   

9.
I ±V profiles of the Fei 5247 and 5250 lines in the 2B flare of June 16, 1989 have been analyzed. A bright knot of the flare outside the sunspot where the central intensity of H reached a peak value of 1.4 (relative to the continuum) has been explored. The Fei 5250/Fei 5247 magnetic line ratio based on the StokesV peak separations of these lines at five evolutionary phases of the flare (including the start of the flare, the flash phase, the peak and 16 min after the peak) has been analyzed. It was found that the StokesV peak separation for the Fei 5250 line was systematically larger than that of the Fei 5247 line. This is evidence for the presence in the flare of small-scale flux tubes with kG fields. The flux tube magnetic field strength was about 1.1 kG at the start of the flare and during the flash phase, 1.55 kG during the peak, and 1.38 kG 16 min after the peak. The filling factor,, appears to decrease monotonically during the flare.  相似文献   

10.
Seventeen coudé spectrograms (dispersion 20 A mm–1) of the Lyrae-type eclipsing binary V 367 Cygni (P=18.6 d) have been studied. The observations were made at the Haute Provence Observatory during a period of almost two years (May 1973–March 1975). An anomalous behavior for the radial velocities of the spectrograms taken during one cycle (406) was observed; it is suggested that gas eruption under form of prominences may explain it. The spectrum is dominated by shell lines very similar to those present in the spectrum of the supergiant A9 Ia Aurigae. The underlying stellar spectrum is classified as A5 I on the basis of the intensity of the sole clearly visible stellar line, 4481 MgII, of the wings of the stellar Balmer lines, and an estimate of the intensity of the stellarK line. The radial velocity curves for the shell lines of CaII, HI, metallic ions and neutral iron, as well as the phase dependence of the microturbulence, indicate stratification in the shell.  相似文献   

11.
The polarization structure in several spectral lines in solar type stars is computed using the method described by McKenna (1981, 1984a). The frequency redistribution function used for these calculations is a linear combination ofR II andR III. The line profiles and polarization structures have been computed for several weak solar resonance lines includingKi 7664 Å, Sri 4607 Å, Baii 4554 Å, for various polar angles along the stellar disk. Both the line profiles and polarization structures as well as the center to limb behavior of the line center polarization agree well with observations.The somewhat stronger resonance line Cai 4227 Å shows a different polarization structure when compared to the weaker solar resonance lines. It is found that for strong resonance lines the proper redistribution function to be used is a linear combination ofR III andR v (see McKenna, 1981, 1984b; Heinzel, 1981). The major reason for this is that for strong resonance lines both the upper and lower levels are broadened by collisions. This violates the assumptions upon which the redistribution functionsR II andR III are based.  相似文献   

12.
The data on the spectrum of the cosmic-ray electron component near the earth, on the radio-spectra of radio-galaxies, quasars and the Crab Nebula, as well as the data pertaining to the X-ray spectrum of the cosmic background, all agree that the sources of cosmic-ray electrons (such as supernovae and galactic nuclei) inject particles characterized by a power spectrumN(E)=KE –0, with 01.5–2.5. A mechanism is known in which the source emits a proton-nuclear component of cosmic rays with a spectrumN n (E)=K n E – n, n = + 2, =w cr/(w–w cr), wherew cr is the cosmic-ray energy density in the source, andw=w cr+w n+w turb, the total energy density. We obtain =2.5 in agreement with observations on the natural assumption that =0.5. Within the framework of the same model with some additional assumptions, the electrons in the source, as well as those ejected by the source, are shown to have a power-spectrum characterized with 0 n = + 2. Thus the model discussed gives an adequate spectrum for both the proton-nuclear and the electron components of cosmic rays.  相似文献   

13.
From a high-resolution spectrum of a sunspot umbra (1.1 < < 2.3 m) we derive models of the temperature stratification in the deep layers of the umbra. The observed spectrum is corrected for straylight using the Hi Paschen line at gl = 1.282 m. A method is described for the iterative fitting of empirical temperature models to spectral information, and the method is applied to the present data. We find that the observed profiles of 3 high-excitation lines of Sii and the observed continuum contrast between umbra and photosphere cannot be reproduced with a single one-component model of the umbral atmosphere: the Si i lines require a model that is 460 K hotter at gt 0.5 = 3 than the continuum model. This indicates that hot and cool components coexist within the umbra. A temperature model derived from the relative intensity in the wings of 3 low-excitation lines of Mgi, Ali, and Sii is not significantly different from the continuum model.Based on observations obtained at Kitt Peak National Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under contract with the National Science Foundation.  相似文献   

14.
In a total of 181 photographic spectrograms, obtained at the Manuel Foster Observatory of the Catholic University in Santiago (Chile), the equivalent widths of the absorption lines HeI 4471 and MgII 4481 have been determined for 10 selected southern Be stars and 4 normal B-type stars. The mean equivalent widths of each star are compared to published mean values from largers samples of B stars. On the average, Be stars coincide with normal B-type stars in their equivalent width. However, a striking difference between rapidly and slowly rotating stars in their line ratios (HeI/MgII) was found, which is probably an artifact due to a systematic misclassification of spectral types of rapidly rotating B stars (v sini>200 km s–1). Six of the ten Be stars show evidence for variability in HeI and/or MgII with time-scales shorter than a few days and amplitudes up to a factor 2 in equivalent width. Line variability occurs in the entire range of projected rotation velocity (70 km s–1<v sini<350 km s–1), but seems to be restricted to spectral types B2-B4. In addition, variations at longer time-scales (years) were observed in two cases. Three of the variable stars (HR 4074, HR 4537, and Ara) present correlated variations in both lines, one ( Cen) anti-correlated variability. We interpret our results in terms of nonradial pulsations and stress the importance to study the HeI/MgII lines and their variability in a larger sample of Be, Bn, and normal B stars, including archival material in order to follow-up line variability for several decades in the past.  相似文献   

15.
Umbral line profiles of H, Na D2 and Hei 10830 have been observed photoelectrically with a pressure scanning spectrometer, URSIES (Ultravariable Resolution Single Interferometer Echelle Scanner). Intermittent pulse counting techniques are applied with integration times as short as 0.8 s which permits selection of moments of good seeing and guiding even in poor climates.The H line profile shows in a medium-sized spot (A u = 100 × 10–6 SH) a pronounced weakening in the wings but a persistence of the line core in agreement with the results of Fricke and Elsässer (1965).The profile of the Hei 10830 line shows an unexpected strengthening over the umbra of the two spots which have been observed. The strengthening of the line in the umbral spectrum of a third spot has been confirmed by Dr. Mallia at the Oxford Solar Station (Gornergrat, Switzerland).Na D2 line profile together with continuum observations at 4260, 5890, and 6530 have been accounted for with an empirical (T, ) relation by one of us (Yun, 1971). The wavelength dependence and the absolute values from 4000 Å to 14000 Å of the intensity curve generated by this relation shows very good agreement with the intensities observed by Wöhl et al. (1970) in a spot of similar diameter.Precision observations of the continuum at 5890 indicate umbra-to-disk continuum ratios that are higher (0.104) than the Mercury calibrated value by Mattig (0.086) even when a maximal correction for scattered light is applied. Only Zwaan's (1965) cool umbral model atmosphere approaches Mattig's continuum value, but this model renders the absorption wings in Na D2 much too deep. It is suggested that future definitive observations should be carried out with coronagraphs under coronal skies or in satellites.Work supported by NASA Grant NGR-39-005-066.  相似文献   

16.
The original temporal analysis of a 12 night spectral timeseries of WR-134 has been found to be flawed and a re-analysis shows that the line profile variations are indeed periodic. When combined with a 4 night timeseries taken 45 days earlier, a period near 2.27 d is found in periodograms of the Heii 5412 line centroid,rms line width, and line skew variations. When the emission line residuals are ordered as a function of phase, a sinuous feature appears to snake about the line center with an amplitude of ± 500 km s–1. This is 20 larger than the line centroid amplitude; the calculation of which is heavily weighted by static portions of the line profile. In addition to the snake, emission residuals appear that move away from line center on unbound trajectories and are thought to result from the interaction of a periodic driver with the unstable flow of the radiation driven wind. The nature of the periodic driver is a topic for discussion.  相似文献   

17.
We have examined seven active regions of the Skylab period in the EUV (Harvard College Observatory), and in H and K3 (Observatoire de Meudon, spectroheliograms and patrols) in order to elucidate the magnetic geometry in the coronal environment of filaments. We have also looked for signatures of magnetic reconfigurations associated with instabilities (i.e. velocities or disappearances) of filaments. Out of sixteen H filaments observed, six were stable (lifetime 48h). All the filaments lay within coronal cavities as seen in lines formed above 1.5 × 106 K (Mgx 625, Sixii 521, Fexvi 417, Fexv 361). None of the stable filaments had arcades or arches spanning the cavities except (sometimes) at the ends of the filaments. On the other hand, most (8/10) of the unstable filaments (having concurrent Doppler shifts or a subsequent DB within 24h) had arcades or single arches spanning their cavities. The arches were observed in EUV lines with formation temperatures as low as 2–4 × 105 K (Oiv 554, Ovi 1032, Ne vii 465), as well as in hotter lines. A statistical test shows that the arcade/instability vs non-arcade/stability association is significant at the 99% confidence level. We suggest 2 types of scenario relating arcades to instabilities. The more preferable scenario is closely related to the Kuperus/Van Tend model of filament disruptions.  相似文献   

18.
The center-to-limb behaviour of the Ba ii 4554 resonance line is analyzed together with data from the extreme limb, flash intensities and profiles of other Ba ii lines. An empirical NLTE method is employed in which the observed profiles are compared with synthesized profiles based on a standard one-dimensional model atmosphere, with the line source function, the barium abundance, the collisional damping and the atmospheric turbulence as free parameters.The line profiles from the extreme limb furnish considerable constraints on the formation of Ba ii 4554. Its wings reverse into emission well inside the solar limb, a phenomenon which cannot be explained by any frequency-independent line source function. Accounting for effects of partially coherent scattering in the line source function is a necessary and adequate step to reproduce the observations both over the disk and near the limb. The form of the empirically derived frequency-dependent line source function is discussed.Results are given for various parameters (gf-values, solar barium abundance and isotope ratios, collisional damping, microturbulence and macroturbulence).The 4554 profile of disk center shows a depression in its blue wing resembling asymetries found in various stellar spectral lines.  相似文献   

19.
We identify the Balmer 9 and 11 lines of He ii at 959 Å and 942 Å in solar spectra. These lines are produced mainly by recombination following photoionization of He ii by coronal XUV radiation. From analysis of the line intensities, we confirm the theoretical model of Avrett et al. (1976), who found that an appreciable amount of He++ is present at temperatures of 1–2 × 104 K and that the anomalously strong He ii 304 line is produced primarily by collisional excitation. We also confirm the suggestion of Kohl (1977) that the photoionization-recombination process is more important in active regions than in the quiet Sun, and we find that the 304 line is produced largely by recombination in solar flares.  相似文献   

20.
Circumstellar peculiarities of the A0-type Herbig stars are analyzed on the basis of high-resolution CCD spectroscopic data, obtained in 1991-1994 at the ESO and the Crimean Astrophysical Observatory (about 250 spectrograms). The results of investigation of the rapid line profile variability in H , H , HeI 5876 and DNa lines are presented for AB Aur, HD 163296, HD 36112 and HD 100546. The conclusion is made that the behaviour of these lines can be explained in the framework of the model containing an equatorially concentrated and azimuthally inhomogeneous stellar wind and an external cool shell occasionally losing matter in the form of infall on to the star.  相似文献   

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