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1.
Cemal Aydin 《Astrophysics and Space Science》1979,64(2):481-507
Twenty-five coudé spectrograms (22 with dispersion 12 Å mm–1 and three 7 Å mm–1) of 6 Cassiopeiae (A3 Ia) have been studied. The observations were made at the Haute Provence Observatory. The results of the analysis suggest a correlation between the variations of the equivalent widths, the microturbulence and the radial velocity. The radial velocity and turbulent velocity present a rapid variation with time, even in intervals as short as about an hour. The hydrogen lines are slightly asymmetric but the strongest Feii lines are clearly asymmetric. We found that the amount of asymmetry of the strongest Feii lines (I>6) correlates with the loggf value, with the estimated laboratory intensityI, and with the equivalent widthW
.The observations have been made at the Astronomical Observatory of Haute Provence (CNRS). This work has been supported by TUBITAK (Scientific and Technical Research Council of Turkey), and partially by CNR (Consiglio Nazionale delle Ricerche) of Italy. 相似文献
2.
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
3.
We have studied high-resolution SWP spectra of AE Aur and
2 Ori A, obtained from the International Ultraviolet Explorer Satellite; and derived curve of growth and column densities ofCii,Cii
*, Alii, Siii, Siii
*,Sii, Crii, Feii, Niii, and Znii. It has been possible to fit these ions on one empirical curve of growth with a velocity parameterb=13 km s–1 for both stars.Based on the observations made by the International Ultraviolet Explorer (IUE), and collected at the Villafranca Satellite Tracking Station of the European Space Agency. 相似文献
4.
The problem of the detection or discovery of RS CVn-type close binary systems with the aid of the magnesium emission doublet 2800 Mgii is discussed. On the example of a star, HD 102077, the possibility of such an approach is shown. The determining factor is the magnitude of the measureless parameterR(Mgii), that is, the relative power of the magnesium doublet emission. For the normal Main-Sequence stars the magnesium emission has a purely chromospheric origin andR(Mgii) 1 (in units of 10–5). However, in the case of close binary systems of RS CVn-typeR(Mgii) 100. Wit the help of IUE it is foundR(Mgii) 100 for the star HD 102077 and, therefore, it is identified with RS CVn-type objects in which the magnesium doublet emission is generated in the intercomponent medium by gaseous matter and is transferred from one component of the system to the other. The basic physical parameters of the intercomponent medium in the case of HD 102077 are obtained. 相似文献
5.
The radial velocity, intensity variations of the Caii line and chemical composition of the suspected magnetic star HD 151 199 have been studied using three 9.6 A/mm and twenty-one 40 A/mm dispersion spectrograms which were taken at St. Michel and Asiago Observatories respectively. The radial velocity and the intensity of the Caii K line suggest a variation with a 6.143 day period. The range is about 40 km/sec for the radial velocity and the K line changes in intensity by 50%. Preliminary results of the photometric data in the Geneva system show a similar trend of variation in (B
2–B
1) with the same period. H and H contours and the Balmer discontinuity give eff=0.50 and logg=4. The most probable microturbulence is found to be 6.4 km/sec. The excitation temperature, exc=0.50, is derived from the Fe lines and adopted for the other elements as well. A quantitative analysis by curve of growth and weighting function method, using Mihalas and Conti's atmospherical models was made. HD 151 199 shows an overabundance of Ca, Sr, Ba, by factors of 2, 40, and 5 with respect to 30 L Mi. Euii is probably overabundant also but it is not possible to give this element a numerical value. The other elements seem to be normal. 相似文献
6.
The 270 chromospheric emission lines of Feii ranging between 2000 and 3200 Å observed by Skylab at a height of 4 (2900 km) above the limb of the quiet Sun are analyzed by the emission curve of growth method, using newly calculated gf-values. It is derived that the excitation temperature is 7.2 × 103 K and that the turbulent velocity is consistent with the previous results that the microturbulent velocity is lower than 10 km s–1 in the cool (<104 K) region of the chromosphere.Contributions from the Kwasan and Hida Observatories, University of Kyoto, No. 270. 相似文献
7.
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
8.
We obtained simultaneous spectra with a spatial resolution of 1/2 and a temporal resolution of 15 s in H, Ca ii-K, Caii 8542 Å, and three Fei lines of the sunspot group responsible for the large flares of August, 1972 (McMath No. 11976). A time series taken 1972, August 3 in the Fei 6173 Å Zeeman sensitive line was analyzed for oscillations of field strength and the angle between the field and the line of sight, and for changes of the field associated with the Ca ii-K umbral flashes discovered by Beckers and Tallant (1969). The power spectra show no significant peaks, conflicting with the results of Mogilevskii et al. (1972) who reported oscillations in the longitudinal component of the field strength with periods of 56, 90, and 150 s. Changes in the field were not observed to be correlated with the occurrence of umbral flashes. These results place restrictions on magnetic modes of energy transport between the photospheric layers and the chromospheric layers where the umbral flashes are observed.The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
9.
Spectroheliogram movies of the solar velocity field have been made in the 4924 line of Feii with a time resolution of 20 sec/frame and a spatial resolution in the range 1–2 sec of arc. A conventional doppler movie has been used to generate two additional movies which show the slowly-varying and oscillatory components of the velocity field separately. A basic result is the simplicity of the field patterns into which the relatively complex velocity field can be decomposed.Operated by the Association of Universities for Research in Astronomy, Inc., under contract to the National Science Foundation.Visiting Astronomer, Solar Division. 相似文献
10.
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
11.
Nova Delphini 1967 has been observed in the red and photographic infrared at the Haute-Provence Observatory from September 7 to November 12, 1968. Dispersions range from 230 Å/mm to 4 Å/mm. The slope of the continuous spectrum in the region 1.3–1.7 –1 leads to a gradient of 3.06, which did not appear to vary during the observing period. This gradient is, however, very different from the value 1.71 measured on plates secured in August 1968. Lines ofHi, Hei, Heii, Feii,Oi,Cii and forbidden transitions due toOi,Oii, Fevii, Fex, Fexi,Siii,Aiii,Av,Axi and Nixv have been identified. Their intensities at various dates are given in Table II. Line profiles could be measured for a few lines taken on a 39 Å/mm spectrogram on October 3. Hei 6678 and 7065 are displayed on Figures 2 and 3. Figure 4 gives the [Oii] doublet at 7319–7330, while the H profile, obtained on October 4 can be seen on Figure 5. The line extends over more than 45 Å and narrow absorptions are seen at 6551.05; 6555.75; 6563.15; 6571.49; 6574.45. Due to the absence of published data on radial velocities of absorption lines in the visible spectrum at that time, it is not possible to give a clear identification for these features. Some of them may belong to H, while others are probably due to metals. 相似文献
12.
A. Keith Pierce 《Solar physics》1991,133(2):215-225
The absolute limb effect is presented for Fei lines 3767 and 3969; for five Tii lines of multiplet 42 near 4535 and one Tiii line at 4534; two lines of Mgi, 4571 and 5172; two lines of Baii at 5854 and 6497. The scattered light of the McMath solar telescope is illustrated by several figures but not applied to the limb-effect observations. It is suggested that the supergravity shift at the limb is the result of scattering of the atoms in anisotropic velocity field.Operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation. 相似文献
13.
From spectroscopic observations of the emission lines H, 4959 and 5007[Oiii], H, 6584[Nii], 6717 and 6731[Sii] and some interferometric data in H and [Nii] it was established that NGC 6164 and NGC 6165 have characteristics of normal Hii regions for Ne and Te. They are embedded in a very tenuous medium nearly coincident with the Strömgren sphere of the central star HD 148937, corresponding to the outer peripheral structure described by Westerlund. Variations of the relative abundances of N, O, and S are discussed. 相似文献
14.
Peter Foukal 《Astrophysics and Space Science》1969,4(2):127-142
A photoelectric Fabry-Pérot spectrometer is used to record the line profiles of H and [Nii] at 22 points in the nebula. The ratio of intensity H/[Nii] is used to derive an electron temperature distribution with values between 5700° and 9100° showing a peak at the centre of density. These temperatures are compared with the H Doppler temperatures to estimate excess velocities of mass motion. Together with the shifts of the H line centres, these lead to an evaluation of the velocity field in the nebula.It is suggested that the nebula consists of a core expanding at about ±10 km/sec–1 surrounded by a thick peripheral shell in which large scale mass motions are small. Non-thermal broadening suggesting turbulent velocities at about the speed of sound is observed in this shell and is attributed to small scale dynamic effects in a non-smooth density distribution. The effect of such expanding cores on heliocentric velocities of galacticHii regions is discussed. 相似文献
15.
This paper presents the results of monochromatic [Oiii], [Nii], and [Sii] observations of ring nebula Sh157 around the star (WR + B0III) HD 219460 belonging to the Ba 3 cluster. A stratification of radiation typical for photoionization excitation has been revealed. The observations suggest that the Sh157 ring structure may arise as a result of the HD 219460 stellar wind blowing the surroundingHii region, and the bubble age is found to bet(2–5)×105 yr. Three outer envelopes have been distinguished: a weaker extended emission shell apparently blown out by the wind from B-stars of the Ba 3 cluster, and two dust shells which are likely to be associated with NGC 7510 and Cas OB2. The paper is also concerned with the discussion of young star aggregates Ba 3, NGC 7510, Cas OB1, OB2, OB4, OB5, OB7, and Cep OBI and the associatedHii regions, shells and supershells of gas and dust, molecular clouds, and supernova remnants which may be probable members of a single giant stellar complex where the star formation process is in progress. 相似文献
16.
The catalog of the classical WR stars which have the emission doublet Ovi 3811, 3834 in their optical spectra (the catalog of the WR-Ovi stars) and the results of the spectroscopic investigations of the WR-Ovi stars HD 16523, HD 17638, and HD 192103 are presented. Rapid spectral variability of the emission doublet Ovi 3811, 3834 in the spectra of WR-Ovi stars HD 16523, HD 17638, and of the emission band 3680-3780 Å in the spectra of the WR-Ovi star HD 16523 is observed. It is shown that spectral sub-types of the stars HD 16523 and HD 17638 as estimated from different criteria are uncertain. We argue that the WR-Ovi stars HD 16523 and HD 17638, the optical spectra of which display emission doublet Ovi 3811, 3834, may be considered as WO5 stars. The sub-type WO5 is proposed for the first time. Classification criteria of the WO5 sub-type are represented. The possible contribution of the ions Heii to the emission at 3811 Å and 3834 Å is investigated. Thez-distributions of WR-Ovi stars and WR stars with the probable relativistic companions are found to be similar. 相似文献
17.
P. Renson 《Astrophysics and Space Science》1972,17(1):69-79
Résumé On compare les courbes de déplacements radiaux déduites des mesures de Struve et Swings, celles déduites des mesures de Babcock et Burd et celle d'Eu déduite des mesures de Pyper (en tenant compte de tous les résultats photométriques, on aP=5,4693±0,0001 j). Les différences sont surtout attribuables, dans le cadre du modèle binaire, à l'effet Ovenden. Celui-ci ainsi que les courants circumstellaires peuvent aussi être responsables des trop grands déplacements constatés et d'autres particularités.
Curves of radial displacements for 2 CVn are obtained by mechanical integration of radial velocity curves deduced from measures by Struve and Swings and by Babcock and Burd for Euii, Crii, Fei andii, and by Pyper for Euii.In order to proceed to the comparison, a value as accurate as possible is sought for the period. If we take all the known photometric observations into account, we get 5.4693±0.0001 d.Small differences between the curves for a given ion are noted, especially when using Pyper's measures. However these discrepancies do not necessarily prove the existence of secular variations; in the binary model, they can be interpreted mainly in terms of the Ovenden effect. Too large displacements, and other pecularities in the variations, may also be attributed to that effect, and to circumstellar currents.The ranges of the velocity variations and of the radial displacements are also discussed for other Ap stars.相似文献
18.
O vi ( = 1032 Å) profiles have been measured in and above a filament at the limb, previously analyzed in H i, Mg ii, Ca ii resonance lines (Vial et al., 1979). They are compared to profiles measured at the quiet Sun center and at the quiet Sun limb.Absolute intensities are found to be about 1.55 times larger than above the quiet limb at the same height (3); at the top of the prominence (15 above the limb) one finds a maximum blue shift and a minimum line width. The inferred non-thermal velocity (29 km s–1) is about the same as in cooler lines while the approaching line-of-sight velocity (8 km s–1) is lower than in Ca ii lines.The O vi profile recorded 30 above the limb outside the filament is wider (FWHM = 0.33 Å). It can be interpreted as a coronal emission of O vi ions with a temperature of about 106 K, and a non-thermal velocity (NTV) of 49 km s–1. This NTV is twice the NTV of quiet Sun center O vi profiles. Lower NTV require higher temperatures and densities (as suggested by K-coronameter measurements). Computed emission measures for this high temperature regime agree with determinations from disk intensities of euv lines. 相似文献
19.
H. Hüseyin Mentese 《Astrophysics and Space Science》1992,187(1):127-133
We have studied the interstellar column densities of Alii, Siii,Sii, Feii, Niii, and Znii in the direction of 18 O- and 6 B-type stars so as to improve the relations of element depletions withE(B-V), and to look for other possible relations with two stellar parameters: namely, the rate of mass loss and rotational velocity. The stars were chosen in order to cover several directions in the Galaxy, as well as a wide range in interstellar reddening. We found a clear inverse trend relating the abundance of elements to interstellar reddening. 相似文献
20.
Some high-dispersion spectrograms of CH Cygni taken in epochs at which only the M6 spectrum is visible and after the explosions of June 1967 and July 1968 have been studied. The strong negative radial velocities of the Caii chromospheric absorptions and the turbulent motions broadening the emission, lines ofHi, Hei, Feii, [Feii] prove that mass is lost from the star at a rate of the order of 10–8 solar masses per year. Arguments are given in favour of the hypothesis that CH Cygni is a close binary composed of an M giant and a blue unstable subdwarf.Presented at the Trieste Colloquium on Mass Loss from Stars, September 12–16, 1968. 相似文献