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1.
High resolution FTS sunspot umbral spectra from NSO/Kitt Peak were used to detect rotational lines due to 11 electronic transitions of the molecule AlF, in the wavelength region 4400 – 9000 Å. The presence of lines due to bands C – A (0,0), (0,1), (0,2) and (1,2), D – A (0,0) and (0,1), F – A (0,0), G – A (0,0), and F – B (0,0) is confirmed. Further, the presence of lines due to C – A (1,0) and (1,1) transitions is treated as doubtful because of heavy blending in the region, by rotational lines of TiO. Among the identified lines, those which are well resolved were selected for measurement of equivalent widths. The measured values for the bands D – A (0,0) and F – A (0,0) were used to estimate the respective effective rotational temperatures to be 1240 ± 120 K and 2390 ± 400 K.  相似文献   

2.
The equivalent widths of P(51) and R(43) lines of the 1-0 and P(45) and R(56) lines of the 2-1 vibration rotation bands of SiO near 8 m region, have been computed for Zwaan's (1974) sunspot model at the centre of the disc. The predicted equivalent widths suggest a possible presence of these SiO bands in the sunspot spectrum.  相似文献   

3.
V. P. Gaur 《Solar physics》1976,46(1):121-123
The equivalent widths of R 1(26.5) lines, belonging to the 1-0, 2-1 and 3-2 vibration-rotation bands of NO near 5.3 m, have been computed for two different sunspot models at four positions on the disc. The computed equivalent widths in both models suggest a possible presence of these NO bands in the sunspot spectrum.  相似文献   

4.
The calculated equivalent widths of some lines of SiO in the umbral spectrum suggest that strong lines of Si28O16, Si29O16 and Si30O16 may be present in the sunspot ultraviolet spectrum. We also find that between 37 000 and 47 000 cm–1 the quasi-continuous absorption of SiO dominates all other absorptions.  相似文献   

5.
High-resolution Fourier transform spectrometer sunspot umbral spectra obtained at the National Solar Observatory/Kitt Peak were used to identify molecular rotational lines arising from the infrared band systems of CrH and CrD molecules. Measurement of the equivalent width used the Gaussian-profile approximation method, which is suitable especially for faint lines. Equivalent widths are measured for an adequate number of best lines of the A – X (0,0) band of CrH and the A – X (0,0;1,0) bands of CrD and, thereby, the effective rotational temperatures are estimated.  相似文献   

6.
Spectral observations of the flare star EV Lac made on the 2.6-m telescope at the Byurakan Observatory in 2000–2002 are reported. A powerful flare was detected and it was possible to follow the variation in the equivalent widths of the Hα and Hβ lines, both during the flare and during the quiescent phase of the star. It is shown that the profiles and equivalent widths of the lines underwent substantial changes. The equivalent widths of these emission lines reached a maximum roughly 40 min after the flare maximum. __________ Translated from Astrofizika, Vol. 49, No. 4, pp. 573–583 (November 2006).  相似文献   

7.
A search has been carried out for the presence of rotational lines of two bands of the (0, 0) and (1, 1) A 1Π?–?X 1Σ+ system of the AlH molecule in the high resolution Fourier Transform Spectra of sunspots observed at the National Solar Observatory at Kitt Peak. Though the presence of the AlH molecule in sunspots was confirmed by Wallace, Hinkle, and Livingston (An Atlas of Sunspot Umbral Spectra in the Visible from 15?000 to 25?000 cm?1 (3920 to 6664 Å), Tech. Rep. 00-001, National Solar Observatory, Tucson, AZ, 2000), there is no report on the rotational temperature in the literature by identifying AlH molecular lines. The results obtained in this new search using a suitable identification technique are compared with the results reported by Wallace, Hinkle, and Livingston (2000). In view of the fact that the rotational temperatures of the molecules could be used to test photospheric and sunspot models, the effective rotational temperature for the (0, 0) band of the A?–?X system of AlH molecule is estimated by measuring the equivalent widths of well resolved spectral lines and its value justifies the existence of the AlH molecule in sunspots.  相似文献   

8.
A flux-calibrated optical spectrum integrated over the entire Crab nebula was obtained by making drift scans with a long-slit spectrograph. Compared to observations obtained over the past 40 years, these new data confirm an earlier controversial result that the [O iii ]  λλ4959, 5007  equivalent width is increasing with time, although the rate of ∼0.9 per cent yr−1 is somewhat slower than that measured previously. Additionally, the Hβ equivalent width is increasing at a comparable rate, but the measured fluxes of both Hβ and [O  iii ] have changed less than their respective equivalent widths. The different rates of change in the measured fluxes and equivalent widths of these lines suggest that the optical synchrotron continuum from the Crab nebula is indeed fading rapidly. The apparent decline is consistent with a rate around  −0.5 (±0.2)  per cent yr−1 at wavelengths near 5000  Å inferred independently from measurements of the optical continuum flux during the same time period.  相似文献   

9.
The sunspot spectrum shows many molecular lines, of which some have been identified. These lines are formed farther out in the sunspot atmosphere than the atomic lines or the continuum, and are thus useful for probing the outer layers. Photographic spectrograms were obtained for three different sunspots under carefully selected seeing conditions, showing molecular absorption lines due to MgH, CaH, and TiO. Analysis led to estimates of the effective rotational temperatures of each; in the case of CaH, no definite conclusions could be drawn. Predicted rotational temperatures and observational f-values were calculated on the basis of model umbral atmospheres due to several authors. A new model was derived from the molecular lines measured here, and shown to differ widely from previous models. The usefulness of photographic spectra for this purpose is seriously questioned, and suggestions are made for new observations.  相似文献   

10.
H. Ruhm 《Solar physics》1969,10(1):104-111
By a curve of growth analysis, using photospheric and umbral equivalent widths, published by Fricke and Elsässer, and absolute oscillator-strengths, it has been found, that the gas pressure in a sunspot is lower than in the corresponding layers of the photosphere. Contribution curves have been computed to get more accurate information to which layers of the spot the results relate, which were derived by comparing on the one hand the damping parts and on the other hand the linear parts of the photospheric and umbral curves of growth.From Mattig's observations of a sunspot near the sun's limb, a scale-height of about 300 km is derived. This indicates a deviation from the hydrostatic pressure stratification.From these empirical results - a similar indication is given by the discussion of the Wilson-effect by other authors - the conclusion is drawn that it cannot be a satisfying method to construct a sunspot model by the a priori assumption of hydrostatic gas pressure, because it seems to hide effects not understood until now. One should try to get with aid of better observations an entirely empirical model.Mitteilungen der Landessternwarte Heidelberg-Königstuhl Nr. 162.  相似文献   

11.
High-resolution spectral observations of 123 B0–B5 stars in the main sequence evolutionary phase were obtained at two observatories, namely the McDonald Observatory (McDO) and the Crimean Astrophysical Observatory (CrAO). Accurate equivalent widths W of two Balmer lines, H β and H γ , and ten He  i lines were obtained for all the stars, as well as of the He  ii   λ 4686 line for the hottest ones. A careful analysis of the measured equivalent widths was performed. It is shown that there is a very good agreement between the W values derived from the McDO and CrAO spectra for 14 common stars. A comparison with published data leads to the conclusion that the W values measured earlier by some authors for strong He  i lines are very likely to be underestimated. Infrared photometric observations in the J , H , and K bands were performed for 70 programme stars. All these data will be used in other papers: in particular for the T eff and log  g determination and for the He, C, N and O abundance analyses.  相似文献   

12.
Sunspot spectra for LiI 6708Å lines and for several FeI and CaI lines were obtained. Observations were performed in January and in August, 2011 using the TST-2 telescope with a charge-coupled camera at the Crimean Astrophysical Observatory. The sunspot models were calculated by using the observing profiles of FeI and CaI lines. Lithium abundance was determined by using the calculated sunspot models and LiI 6708Å observed profiles; this equals log(N Li) = 0.98 and 0.95 (in the scale logA(H) = 12.0).  相似文献   

13.
Ba II line equivalent widths appear to be well correlated with the absolute magnitudes for yellow supergiants. Two Ba II lines 5853.6 Å and 6141.7 Å were applied for investigation of the possible relation between their equivalent widths and Mv for small-amplitude Cepheids and non-variable supergiants.  相似文献   

14.
Equivalent widths of weak and moderately strong Fraunhofer lines observed in an area roughly 3500 × 10000 km in extent are found to show small variations of the order of 1 mÅ, on a time scale of minutes. The dependence of amplitude on line strength and excitation closely fits that predicted for a compressional disturbance associated with temperature variations that manifest themselves in the equivalent widths. The rms amplitude is about 20K near τ5000 = 10-2. These equivalent width variations frequently exhibit a 5-min periodicity and are accompanied by prominent oscillations of velocity. Power spectra of both quantities closely resemble each other and demonstrate that most of the equivalent width variations in the range 200 to 500 s are due to the thermal response of the atmosphere to 5-min oscillations. A systematic phase lag between velocity and equivalent width is observed, in the sense that temperature leads velocity by an average angle of 120°. This deviates significantly from 90° valid for standing adiabatic waves, showing that in the line-forming layers, τ5000 ≈ 10-2, the 5-min oscillations are markedly affected by radiative exchange. The observed phase lag implies a radiative decay time of ≈40 s, a value which agrees with modelatmosphere predictions for the line-forming layers. Since the observed wave trains frequently show constant amplitude over a much longer time, a continuous feed-back of energy seems to occur.  相似文献   

15.
The effects of reflection on the formation of spectral lines is investigated. We have assumed a purely scattering atmosphere and studied how the equivalent widths change due to irradiation from the secondary. Generally, the flux in the lines is increased at all frequency points, the cores of the lines receiving more flux than the wings. Moreover, the proximity of the secondary component changes the equivalent widths considerably. The further away the secondary is from the primary the higher are the equivalent widths.  相似文献   

16.
Ultraviolet absorption by H2O and other species in the comae of comets could be detected by studying, with satellite telescope-spectrometers, the occultation of hot stars by comets. Such observations could produce the first direct detection of H2O, the fundamental parent molecule in comet comae, and give measures of molecular level populations. The first instrument suitable for such observations will be the High Resolution Spectrograph on Space Telescope and, therefore, we consider its capabilities. We have used a Haser model to estimate the molecular column densities and to predict equivalent widths for lines of H2O, OH, CO, and O as functions of time and angular distance from a comet with a high H2O production rate. We have determined the minimum detectable equivalent widths, and therefore, the maximum angular separation from such a comet at which H2O, OH, and CO could be studied. A conservative, statistical estimate shows that comets with high water production rates should pass near enough to about 10 to 100 stars suitable for absorption studies of the CX band of H2O (1240 Å). Estimated equivalent widths for CO, OH, and the resonance lines of C and O indicate that these species may also be detected.  相似文献   

17.
Results from a spectral study of the quasar Kaz 102 are presented. It is shown that its spectrum varies as a whole; that is, the parameters of both the lines and the continuum change. Based on a comparison of results presented previously and in this paper, it is concluded that over a time of approximately 27.5 years the equivalent widths and relative intensities of the lines have increased, while their half widths have decreased. The spectral composition of Kaz 102 has also changed: new lines, HeII λ4686, [OIII] λ4363, and others, appear in spectra of 2000 and 2001 which were not observed in spectra taken in 1973. The electron density, and the mass and effective radius of the gas component are determined to be 2·107 cm-3, 2·104 M⊙, and 0.2 pc. __________ Translated from Astrofizika, Vol. 50, No. 2, pp. 161–170 (May 2007).  相似文献   

18.
We have analyzed the properties of oscillations in a sunspot based on SDO observations with a duration of 6 h. The 3-min oscillation spectrum has turned out to consist of dozens of spectral lines. The line widths are at the spectral resolution limit. The oscillations in a sunspot have been broken down into individual areas with a size of a few arcseconds, each having its own oscillation spectrum. These oscillation properties cannot be explained in terms of the existing models based on the assumption that the sunspot oscillates as a whole. We propose a model of local oscillations that explains the complex spectrum of the oscillations and their locality. We show that in addition to the chromospheric resonator, there exists a subphotospheric resonator for slow MHD waves. The existence of this resonance layer allows the locality of the oscillations and their complex spectrum to be explained in terms of Parker’s model.  相似文献   

19.
During the total eclipse of ε Aur, 18 spectra in the Hα region were taken in rapid succession on 1983 March 9, and 6 spectra on March 10, with the Reticon at the Coudé focus of the McDonald Observatory 2-metre telescope. The data were processed and plotted by computer. Variations on short time-scales were observed in the radial velocities of the metallic lines and Hα. The radial velocities of individual metallic lines are between 3 and 16 km/s more negative than calculated from the orbital elements. The Hα has 3 emission features with equivalent widths 300 mÅ, 54 mÅ and 1 mÅ and 1 absorption feature with an equivalent width of 1800 mÅ. The profile and the equivalent widths changed only slightly while substantial variations occurred on the blue side of the two stronger emission features. The radial velocities of the emission features are about ?60, +12 and +57 km/s; that of the absorption component is +20 km/s. The radial velocity of the strongest emission feature also varies, but by much smaller amounts than the metallic lines and the variation appears to be periodic. A model in which the secondary is a B-star surrounded by hot, active clouds is proposed.  相似文献   

20.
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