共查询到20条相似文献，搜索用时 78 毫秒
1.
M. Mamadazimov 《Solar physics》1972,22(1):129-136
The fine structure of the Evershed effect was studied using spectrograms obtained on 3 July 1969 at the Pulkovo Observatory. The results of the study of Fei and Cai lines show that the outward motion in the penumbra is concentrated only in dark filaments. It is supposed that interfilamentary spaces are parts of the photosphere not covered by dark filaments. The velocity variation along a few dark filaments shows that maximum velocity is at a distance 0.8 Rs from the center of the sunspot. The mean velocity in the interfilamentary elements is of the same order as that in the photosphere directly adjoining the penumbra. The results of measurement in Ti ii, Fe ii and CH lines show that in the colder upper part of the penumbra (CH) the velocity is greater than the velocity measured in the deeper layers (Feii and Tiii). The mean velocity at the outer boundaries of the dark filaments (Tii) is 1.5–2.0 km/s. 相似文献
2.
Y. Öhman 《Astrophysics and Space Science》1988,144(1-2):353-356
Attention is drawn to flare-like plages showing the resonance lines of Nai and Mgii as strong emission lines. Spectra of such objects may prove of interest for the study of electric quadrupole lines of the type 32
S-n
2D.Paper dedicated to Professor Hannes Alfvén on the occasion of his 80th birthday, 30 May 1988. 相似文献
3.
J. Koza 《Solar physics》2010,266(2):261-275
We examine the sensitivity of selected Ba?ii, Fe?i, Fe?ii, and Cr?i spectral lines to changes of the line-of-sight velocity by sharpness of their line profiles and response functions to line-of-sight velocity evaluated by the 1-D model of the quiet solar atmosphere in the LTE approximation. The set of selected lines includes the Ba?ii 4554 Å line, generally considered to be an excellent Doppler mapper. Our findings confirm earlier results showing that the sensitivity increases not only with wavelength, as anticipated from the Doppler relation, but mainly with the sharpness of line profiles given by the ratio of their depths and widths. The line Fe?i 5247 Å is the most sensitive in our set, whereas the Fe?i and Fe?ii infrared lines show very low sensitivity because of their large thermal widths. The line Ba?ii 4554 Å shows only moderate sensitivity due to its large width, given by a broad hyperfine structure and isotopic split. For the first time we identify a very promising and so far unknown Doppler mapper of the solar photosphere and low chromosphere, which is the line Ba?ii 6497 Å. Its sensitivity is comparable with the sensitivity of Fe?i 5247 Å and clearly surpasses the sensitivity of Ba?ii 4554 Å. The line Ba?ii 6497 Å offers many advantages, making it a highly recommendable choice for future studies of line-of-sight velocities in the photosphere and low chromosphere. 相似文献
4.
Among manganese stars, Herculis is of great interest because of the unusual strength of the scandium lines. We present intensity measurements for numerous lines ofCii, Mgi, Mgii, Siii, Caii, Scii, Tiii, Crii, Mni, Mnii, Fei, Feii, Coii, Srii,Yii, and Zrii. 相似文献
5.
B. N. G. Guthrie 《Astrophysics and Space Science》1982,85(1-2):315-324
Four spectra of the long-period Ap star HR 465 were taken in 1969–70 near its rare-earth minimum phase and analysed. Equivalent widths or upper limits were obtained for lines of 23 elements. Lines of Cr were very strong. The relative abundances of the iron-peak elements were derived by a differential curve-of-growth analysis using Gem as the comparison star. The Sc/Fe, Ti/Fe, V/Fe, and Ni/Fe abundance ratios were found to be abnormally low, while the Cr/Fe ratio was abnormally high (0.08). The equivalent widths in 1969–70 were compared with those measured by Aller on a spectrum taken in 1960 near the rare-earth maximum phase. Ionized lines of Sc, Ti, V, Te, Nb, Mo, and the rare-earths all vary out of phase with the Cri and Crii lines. Although Mo and Cr occupy corresponding positions in the periodic table, the Mo/Cr abundance ratio was apparently at least 180 times higher in 1960 than in 1969–70. 相似文献
6.
The center-to-limb wavelength shifts of the cores of faint, medium and strong Fraunhofer lines are presented: Fei 3767, Caii 3968, Ceii 4222, Cai 4227, Nai 5896, Baii 6497, and Ki 7699.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation. 相似文献
7.
M. J. Stift 《Astrophysics and Space Science》1977,46(2):465-469
A detailed analysis of the multiplet structure of lines used for observations of stellar magnetic fields is presented. It is shown that LS-coupling does not hold good for many of the spectroscopic terms of Tiii and Crii and that the magnetic fields observed in several magnetic stars are strong enough to produce transition to the Paschen-Back effect in some of these lines. In order to avoid possible erroneous results it is recommended that only lines originating from Russell-Saunders terms be used for magnetic observations. A list of Tiii, Crii and Fei lines is given which should not be used in measuring strong magnetic fields in magnetic stars. 相似文献
8.
Brigitte Schmieder 《Solar physics》1976,47(2):435-460
Using a 32 minutes sequence of observation, brightness and velocity fluctuations in the wings of the Mgi line at 5172.7 Å and Fe ii line at 5197.578 Å are analysed. The analysis of phase shifts and amplitude ratios leads to the following conclusions:
| (1) |
In the frequency range from (400s)–1 to (130s)–1, we find the existence of three modes of waves: internal gravity, evanescent and propagating acoustic waves which appear with increasing frequency. A satisfactory agreement for velocity between observations and theory in the range of horizontal wavelengths \s>5000km with a theoretically local relaxation time
–180s-40s is obtained.
The calculation of intensity fluctuations shows that the Mgi line is sensitive to temperature and density fluctuations while the Fe ii line is only sensitive to temperature perturbation. For the best fit with the same value of
–1 to both lines (i.e., Fe ii and Mg i) it is found necessary that the density effect should be taken into account for the Mg i intensity fluctuations. The relaxation time deduced from observed intensity fluctuations seems to decrease with the period of oscillation. This suggests the presence of a dissipation process. 相似文献
9.
High resolution spectroheliograms in the ultraviolet emission lines He i, He ii, O iv, O v, and Ne vii have been photographed during a sounding rocket flight. Simultaneously, broad band filtergrams of the far ultraviolet solar corona were obtained from the same flight. This paper describes qualitatively the spatial distribution of the UV emission. A comparison with an H filtergram is made. The most significant results can be summarized as follows: We find most of the ultraviolet emission concentrated around spicules, with different degree of concentration, decreasing with higher temperatures. 4 different areas of ultraviolet emission can be distinguished. (1) The normal network, bright in all UV emission lines from the chromosphere into the corona. (2) The coronal holes, bright in all UV emission lines up to 600 000 K but depressed in coronal lines from 1 million degrees upward. (3) The coronal depressions near active centers, absence of all ultraviolet emissions and (4) Active regions, where ultraviolet emission comes from plages, sunspots and coronal loops. High non-thermal Doppler velocities can be found in certain plage kernels around 105 to 2 × 105 K. Sunspots are bright in the ultraviolet, but do not exhibit He i or He ii emission. The corona above sunspots is weak. Sunspots do not show high non-thermal Doppler velocities. The He i and He ii emission does not follow either chromospheric, transition zone or coronal pattern; one can recognize some typical behavior of each. 相似文献
10.
Bruce W. Lites 《Solar physics》1973,30(2):283-300
Mean profiles of eighteen neutral iron lines of varying strengths were measured at selected positions from the center of the solar disk to the limb. These profiles were obtained by rapid photoelectric scanning of the spectrum with a double-pass spectrometer. The Fe i lines selected are representative of most of the stronger low-lying transitions in the neutral iron atom. In addition to the iron lines, this observational program includes center-to-limb measurements of three Ti ii lines and of the Ca i resonance line 4226.7. The line profiles are presented here in graphical form after correction for instrumental effects and normalization to the local disk center continuum.Both Kitt Peak National Observatory and the National Center for Atmospheric Research are sponsored by the National Science Foundation. 相似文献
11.
The hydrogen and helium lines are the most prominent lines in the solar prominences spectra. Observations with the SUMER spectrometer
onboard SOHO showed that there are weak lines in the blue wings of the Lyman series which affect their profiles. They were
all identified as He ii lines in the Lyman series wings, except for the Lα line whose profile was affected by the use of an attenuator. The He ii lines are the even Balmer lines of the He ii system, a set of lines that we complete with the odd ones. We characterize them by comparison with the blue wings of the
Lyman series in order to improve the H Lyman series observations and modeling, on one hand and to provide He ii lines observations for further combined H – He i – He ii modeling, on the other hand. 相似文献
12.
A detailed list and analysis of line identifications of five UV spectra of the RS CVn-type binary system TY Pyxidis are presented. These spectra are recorded at different phases with the International Ultraviolet Explorer (IUE). Two of them are in the wavelength range1235–1950 Å while the other three in the range2700–3110 Å.The far-UV spectrum of TY Pyx is mainly an emission spectrum dominated by the emission lines of the ions:Ci, Oi, Cii, Siii, Heii, Alii, and Feiii. We also pointed out the existence of a Feiii [34] line in absorption.The UV spectrum between 2700–3110 Å is dominated by weak absorption lines. Two satellite components are indicated for many lines, which correspond to the two stars of the system, in the two out of the three spectra (LWP 13386 and LWP 13347).Violet emission wings are observed for Fei [1], Tii [1],Oiv [1], and Siiii [1]. The UV spectrum of TY Pyx is also characterized by the multi-structure of Mgii [1] resonance lines.Based on data from the International Ultraviolet Explorer, de-archived from the Villafranca Data Archive of the European Space Agency. 相似文献
13.
F. Baudin E. Ibarra E. H. Avrett J.-C. Vial K. Bocchialini A. Costa P. Lemaire M. Rovira 《Solar physics》2007,241(1):39-51
We present SUMER/SOHO UV measurements of chromospheric oscillations of intensity, velocity, and linewidth observed in C i, S i, O i, and C ii lines, which are formed in the altitude range from 1000 km to 2000 km above τ
500=1. Oscillations in lines originating at similar altitudes exhibit different behaviors which we discuss in terms of the formation
of the lines. 相似文献
14.
E. Biémont 《Solar physics》1978,56(1):79-86
Oscillator strengths calculated by the STF method for selected transitions of V i and Co i have permitted to deduce, from an LTE study of weak lines, photospheric abundances in agreement with those obtained from carbonaceous chondrites. A summary of results is also presented for all the iron-group elements. 相似文献
15.
George L. Withbroe 《Solar physics》1969,9(1):19-30
The center-to-limb variation of equivalent widths of 198 Fei lines in the spectral region 5500 to 7000 Å was studied with five photospheric models. The gf-values of Corliss and Warner (1964) were used in the analysis. The photospheric iron abundance was found to vary with excitation potential. This can be explained by a systematic error in the gf-values of high excitation lines and an error of 250 to 500K in the temperature of the arcs used for measuring the gf-values. Departures from LTE in the solar Fei lines are also a possibility. The adopted photospheric abundance of iron, log(N
Fe/N
H) is - 5.2. 相似文献
16.
IUE ultraviolet spectral recording for a low excitating planetary nebula NGC 6369 is obtained. The very strong doublet 2800 Mgii in emission as well as not less strong absorption line 2852 Mgi are discovered in the spectrum of this nebula. It is shown that the resonance line 2852 Mgi may originate only in a neutral envelope, around the nebula, consisting of neutral hydrogen, neutral magnesium, and dust particles (Hi+Mgi). The importance of this absorption line as a powerful indicator of the discovery of neutral envelopes around the planetary nebulae is outlined.The possibility of the existence of one more envelope—transition zone—immediately contacting with the bright that is ionized part of nebula (Hii+Mgii) is also shown. The transition zone consists of neutral hydrogen, ionized magnesium, and dust particles (Hi+Mgii), main parameters of this zone are also obtained (Table IV).The temperature of the central star of this nebula is obtained for the first time:T
*=48000 K. Continuous background in the interval 2600–3000 Å is identified with Balmer continuum with electron temperatureT
e
=12500 K. 相似文献
17.
H. Holweger 《Solar physics》1973,30(1):35-37
It is shown that depth-dependent departures from LTE such as obtained by Athay and Lites (1972) will not notably affect the solar curve-of-growth of Fe i. This implies that both abundance and microturbulence may be determined from this curve-of-growth assuming LTE, and excludes that microturbulence is an artefact produced by non-LTE effects. 相似文献
18.
Spectra from 2678-2931 Å were obtained of an active region during the 19 June 1974, flight of the University of Hawaii rocket-borne echelle spectrograph. We report behavior of the Mg i and ii resonance line cores in quiet Sun, plage, sunspot, and filament structures. Among the interesting variations in these lines we discern a strong suppression of the red Mg ii emission peaks and possible rapid changes in the Mg i core in the spatially partially resolved sunspot. 相似文献
19.
The line-centre-magnetogram technique has been used to measure the average velocity in magnetic elements in plages and isolated magnetic elements (including dipoles) in Ca ii 8542, Mg i 5183, Fe i 8688 and C i 9111. The velocities vary from 0.6 km s–1 downflow in the line of deepest origin to zero in the highest. The smooth curve obtained by combining these with the results of other investigators is in conformity with Giovanelli's (1977) theory of inflow in the neighborhood of the temperature minimum.This material is based upon research supported by the National Science Foundation under its contract No. AST 74-04129 with the Association of Universities for Research in Astronomy, Inc., for management, operation and maintenance of the Kitt Peak National Observatory.Visiting Astronomer, Kitt Peak National Observatory. 相似文献
20.
Previously published solar abundances of oxygen and carbon can be corrected to be logN(O) = 8.93 and logN(C) = 8.60 on the hydrogen log-scale when new accurate forbidden electric quadrupole transition probabilities A
Q(s–1) are used. Such A
Q's, based on the new atomic structure and electron correlation theory, developed recently by Sinanolu and coworkers, are reported for the (1
S
0-1
D
2) lines of [C i], [N ii, [O i] and [O iii] and the (2
P-2
D) lines of [N i] and [O ii]. The available experimental values are also given for comparison.Work supported by Grant No. GP-29471 from the U.S. National Science Foundation. 相似文献
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