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1.
E. Haugen 《Solar physics》1969,9(1):88-101
The wavelength shifts of approximately 8000 absorption elements in the H-line from spectra of 66 different sunspot regions have been measured.The average velocity field in the chromosphere close to sunspots is determined. Inside 15000 km from the spot's penumbral rim the average velocity vector is directed towards the spot and downwards in the chromosphere; the angle with the horizontal direction is on the average equal to 20°. The magnitude of the average velocity vector shows a maximum of 6.8 ± 1.2 km/sec just outside the penumbral rim and decreases quickly with increasing distance from the spot. Outside 15000 km from the penumbral rim the average velocity vector is small (-0.7 km/sec) and directed nearly vertically outwards from the sun. No significant tangential component of the average velocity field is found.The deviations of the individual elements from the average velocity field are on the average larger than the value of the average velocity. The total rms deviation in the line of sight velocity is equal to 6.8 km/sec. Thus, a large number of elements, as used in this investigation, is required to give significant values of the average velocity vector.We have also observed velocities in the penumbra. The average velocity vector is here probably small and its direction uncertain. The rms deviation in the line of sight velocities observed in the penumbra is equal to 7.5 km/sec.  相似文献   

2.
A group of coronal prominences appeared over a large sunspot group near the central meridian on October 29, 1972. The bright points, which were most clearly seen on the H-image taken at the line center, are interpreted as the points of inflow of the prominence matter into the penumbra. The amount of mass transported by the largest prominence among the group is found to share a considerable fraction of the total mass which may be contained in the permanent coronal condensation over the spot group. The observational data for the microwave emission from the spot group is discussed in relation to this phenomenon.  相似文献   

3.
We present a possible formation mechanism of the asymmetry in the maser emission line of H2O sources associated with star-forming regions. Observations with the RT-22 radio telescope at the Pushchino Radio Astronomy Observatory are used. We analyze the line profiles of emission features in the sources G43.8-0.1, NGC 2071, and ON1. If the line is asymmetric, the left (low-velocity) wing is higher than the right wing. The proposed mechanism accounts for the observed asymmetry and makes it possible to estimate some physical parameters of the medium in the vicinity of a maser spot.  相似文献   

4.
We analyze the spectral line broadening of those magneto-sensitive lines in solar magnetized atmospheres. The broadening at the line wings is due to the increase of the effective width of energy levels involved in Zeeman splitting, and the broadening at the line core also originated in Zeeman splitting under the condition that the Zeeman components are mixed. Therefore, the magnetoinduced or Zeeman broadening take effects on the whole line. The observed Stokes parameter data in a sunspot and outside it acquired by Solar Stokes Spectrum Telescope (S3T) are analyzed for the demonstration of this mechanism, and the Zeeman broadening rates are calculated for FeI6302.5 under some assumptions. Our result shows that the broadening is increased as the magnetic field strength becomes stronger, but the rate of increase at the line core is decreased as the field strength increases, while the rate at the wing does not show such an obvious regularity. The broadening is more effective in the line core than in the wings.  相似文献   

5.
本文对８个活动区极性反转线（中性线）附近黑子半影纤维的形态进行了分析得出：１）具有强δ磁结构的活动区，穿过主要异极性黑子间的中性线近旁半影纤维或多或少地与中性线平行（交角小于３０°），有关黑子半影呈旋涡形态；２）由新浮现发展形成的δ结构区，异级黑子在大黑子边缘或与大．黑子本影之间有一段距离，中性线两边的半影纤维有序排列，走向与中性线斜交，有关黑子呈弱的旋涡形态。３）对于较稳定的极群，Ｎ、Ｓ极性间的宽窄不一的半影稀疏区，中性线沿该区经过，两旁半影松散齿状，走向与中性线大体垂直，相反极性本影间距较远。  相似文献   

6.
Emission core widths of K Ca ii line in the umbra and penumbra of 9 sunspots and in their vicinity are measured. All sunspots are located near the solar disc center. Data on variation of widths W K along the mean sunspot radius are obtained. Values W K in the umbra and penumbra centers are equal or somewhat less than on stars of the same luminosity.  相似文献   

7.
From enlargements of patrol photographs of the disk passage of the sunspot of July 20 – August 2, 1966, intensity profiles across the spot are obtained at several positions near the disk-center and at each limb. It is found that these profiles show asymmetric features near each limb (increasingly sharp limb-side penumbra and poorly resolved disk-side penumbra) which are similar to those reported in Paper III of this series. It is suggested that these profile asymmetries are the essential feature of the center-limb variations in the appearance of a sunspot which have become known as the Wilson effect.Conventionally the Wilson effect is described as the extreme foreshortening and eventual disappearance of the disk-side penumbra and, recently, Suzuki has referred to this as the occultation of the penumbra by the photosphere. We find no evidence at all for the disappearance of the disk-side penumbra at the limb in this spot. Defining half-height points on the profile curves as the umbral and penumbral boundaries, we find that, near the west limb where the spot is stable and regular, the limb-side penumbra increases by about 10% at the expense of the umbra. This result qualitatively supports the results reported in Paper III although it is smaller in magnitude.Other observations of sunspots which appear to exhibit the conventional Wilson effect are discussed and it is concluded that in no case yet published is the resolution and seeing of sufficient quality to demonstrate unambiguously the disappearance of the disk-side penumbra.  相似文献   

8.
The generation of magnetic flux in the solar interior and its transport from the convection zone into the photosphere, the chromosphere, and the corona will be in the focus of solar physics research for the next decades. With 4 m class telescopes, one plans to measure essential processes of radiative magneto‐hydrodynamics that are needed to understand the nature of solar magnetic fields. One key‐ingredient to understand the behavior of solar magnetic field is the process of flux emergence into the solar photosphere, and how the magnetic flux reorganizes to form the magnetic phenomena of active regions like sunspots and pores. Here, we present a spectropolarimetric and imaging data set from a region of emerging magnetic flux, in which a proto‐spot without penumbra forms a penumbra. During the formation of the penumbra the area and the magnetic flux of the spot increases. First results of our data analysis demonstrate that the additional magnetic flux, which contributes to the increasing area of the penumbra, is supplied by the region of emerging magnetic flux. We observe emerging bipoles that are aligned such that the spot polarity is closer to the spot. As an emerging bipole separates, the pole of the spot polarity migrates towards the spot, and finally merges with it. We speculate that this is a fundamental process, which makes the sunspot accumulate magnetic flux. As more and more flux is accumulated a penumbra forms and transforms the proto‐spot into a full‐fledged sunspot (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

9.
This paper is devoted to the effects of dark starspots on observed light curves and line profiles. A new formulation of the starspot model with multiple spots and arbitrary spot shapes is derived which allows for a numerical solution of light and colour curves and distorted line profiles simultaneously. The effects of differential rotation and the existence of a penumbra have also been considered. A parameter study demonstrates the influences of different spot parameters on the theoretical light curves and rotation profiles. The computer code is applicable for single stars as well as for eclipsing close binaries allowing for ellipticity effect and reflection effect.  相似文献   

10.
Balthasar  H. 《Solar physics》1999,187(2):389-403

The magnetic field strength in sunspots was derived from time series of two-dimensional spectra taken with the Göttingen 2D-spectrometer at the Vacuum Tower Telescope on Tenerife in August 1997. For the present measurements the magnetically sensitive line Fe?i 684.3 nm was selected. The main spot of the investigated sunspot group has a maximum magnetic field strength of 2270 G. Enhanced power of the magnetic field variations was found at the boundary between umbra and penumbra for all frequency ranges. These fluctuations are not well correlated with those of intensity variations or line shifts. Other spatial power peaks occur in a dark patch inside the centreside penumbra and at the centres of some accompanying small spots. Since no clear peaks at certain frequencies are found, the variations are not harmonic oscillations. A possible relation to Hα flares is investigated. There are several cases of published observations of magnetic field variations where flares occurred soon after the measurements, but very little before. Therefore it is not very probable that flares act as exciters of magnetic field variations.

  相似文献   

11.
We observe vertical velocity oscillations in some sunspot umbrae with periods of about 180 s and peak to peak amplitudes up to 1 km s–1. These oscillations are not visible in either the line depth, line width or the continuum intensity. No correlation seems to exist between the occurence of these oscillations and the presence of the chromospheric umbral flashes (Solar Phys. 7, 351, 1069). In the spot penumbra there is an indication of a long period oscillation, the period increasing from about 300 s in the inner penumbra to nearly 1000 s at the penumbra-photosphere boundary. An attempt has been made to interpret these oscillations in terms of gravity or acoustic waves, travelling along the magnetic field lines, taking into account the variation of scale height and magnetic field direction across the sunspot.  相似文献   

12.
Observations of the relation between continuum intensity and magnetic field strength in sunspots have been made for nearly five decades. This work presents full-Stokes measurements of the full-split (\(g = 3\)) line Fe i 1564.85 nm with a spatial resolution of \(0.5^{\prime\prime}\) obtained with the GREGOR Infrared Spectrograph in three large sunspots. The continuum intensity is corrected for instrumental scattered light, and the brightness temperature is calculated. Magnetic field strength and inclination are derived directly from the line split and the ratio of Stokes components. The continuum intensity (temperature) relations to the field strength are studied separately in the umbra, light bridges, and penumbra. The results are consistent with previous studies, and it was found that the scatter of values in the relations increases with increasing spatial resolution thanks to resolved fine structures. The observed relations show trends common for the umbra, light bridges, and the inner penumbra, while the outer penumbra has a weaker magnetic field than the inner penumbra at equal continuum intensities. This fact can be interpreted in terms of the interlocking comb magnetic structure of the penumbra. A comparison with data obtained from numerical simulations was made. The simulated data generally have a stronger magnetic field and a weaker continuum intensity than the observations, which may be explained by stray light and limited spatial resolution of the observations, and also by photometric inaccuracies of the simulations.  相似文献   

13.
Spatial scans with a resolution of 3.4 arc sec of the broad-band circular polarization of several sunspots have been made in five filter bands over the wavelength range 0.4–1.7µ with a sensitivity of 1 × 10–6 fractional polarization. The scans, across a spot through the penumbra and umbra center, revealed two important features: (1) The broad-band circularly polarized fluxV reverses in sign, or diminishes to near zero, at the center of the umbral region relative to the outer penumbra. This effect was wavelength dependent and was most clearly detected as a definite reversal in a band at 1.2µ, although a reversal was also detected in a very broad band extending from 0.8 to 1.6µ. (2) There is a marked asymmetry: in all cases the limbward penumbral region exhibited strongerV values than did the disk-center (inward) side of the spot, at all observed wavelengths. Such previously unreported structure in the magnetic circular polarization of sunspots provides new clues for understanding the anomalous large broad-band polarization at short wavelengths and at the same time imposes new constraints on sunspot models. For example, the polarization reversal in the umbra relative to the penumbra can be naively explained by return-flux sunspot models; but this is not the only interpretation. Alternatively, it can relate to reversals in mass-flow velocities and/or vertical velocity gradients, as between the umbra and penumbra.  相似文献   

14.
N.I. Kobanov 《Solar physics》2000,196(1):129-135
It is suggested that the problem of the extent of the outer penumbra could be considered by investigating the range over which the influence of the penumbra on the oscillation regime of the surrounding medium extends. In summer 1998, velocity oscillations were observed in the vicinities of the penumbra of the NOAA 8263 sunspot. The observations were carried out in the H line (chromosphere) and in the far wing of Nii 4857.2 Å (lower photosphere) simultaneously. The oscillation regime typical for sunspot penumbrae is observed within distances of about 15 from the visible outer boundary of the penumbra.  相似文献   

15.
The results of investigations of the Hα and Hβ lines in the spectrum of the star HD 206267 are presented. Observations were carried out in 2011–2014 at the Cassegrain focus of the 2-m telescope of the Tusi Shamakhy Astrophysical Observatory of the National Academy of Sciences of Azerbaijan using an echelle spectrometer. The following features have been revealed for the first time: the moving discrete absorption components in the core of the Hα line from the red side to the violet, the stable emission in the violet wing of the Hα line, the antiphase variation of the radial velocities and equivalent widths of the Hα line, and the independence of the changes of the equivalent widths of the Hβ line from the phase of the orbital period. No spectral features according to which this star could be considered as a source of X-ray radiation have been found.  相似文献   

16.
Sunspots block the flow of energy to the solar surface. The blocked energy heats the volume beneath the spot, producing a pressure excess which drives an outflow of mass. Linear numerical models of the mass and energy flow around spots were constructed to estimate the predictions of this physical picture against the observed properties of sunspot bright rings and moat flows. The width of the bright ring and moat are predicted to be proportional to the depth of the spot penumbra, in conflict with the observed proportionally of the moat width to the spot diameter. Postulating that spot depths are proportional to spot diameters would bury the moat flow too deeply to be observed, because the radial velocity at the surface is found to be inversely proportional to the depth of the spot penumbra. The radial velocity at the surface is of order a few hundred meters per second after 1 day, in agreement with the observed excess of moat velocities over supergranule velocities.  相似文献   

17.
刘庆忠  胡福民 《天文学报》1995,36(3):294-300,T001
本文分析了ＮＯＡＡ６３６１活动区中的一些现象，发现该活动区在衰亡阶段经历了两次同极性黑子的复合过程，复合后的黑子本影间均有光桥存在，观测结果倾向于支持Ｐａｒｋｅｒ１９７９年提出的黑子多磁流管模型。１４日复合后的黑子本影还顺时针方向旋转了约７０度角，从半影纤维的同样顺时针旋转可以认为：该黑子的半影磁场并非是普遍认为的简单的本影磁场的发散部分。我们还观测到另外两个比较有趣的现象：①δ黑子中的ｐ极性黑子  相似文献   

18.
Ratios of the intensity in the core of the Ca ii K line to the intensity of the H line core across a sunspot (SPO 5007) were determined from measurements of spectra made simultaneously with the Echelle spectrograph at the Vacuum Tower Telescope, Sacramento Peak Observatory. The measured values averaged over the neighboring nonspot region, the penumbra and the umbra are found to be 1.13 ± 0.04, 1.19 ± 0.05, and 1.25 ± 0.03, respectively.This work was supported by the U.S.-Republic of Korea Cooperative Science Program (K-24).  相似文献   

19.
The S(1) line of the pressure-induced fundamental band of H2 was identified and measured in the spectra of Saturn and Jupiter. This broad line at 4750 cm?1 lies in a region free from telluric and planetary absorptions. It is about 99% absorbing in the core; the high-frequency wing extends to at least 5100 cm?1. We compare the obseved line shape to the predictions of both a reflecting-layer model (RLM) and a homogeneous scattering model (HSM). The RLM provides a good fit to the Saturn line profile for temperatures near 150K; the derived base-level density is 0.52 (+0.26, ?0.17) amagat and the H2 abundance is 25 (+10, ?9) km-amagat, assuming a scale height of 48 km. The Jupiter line profile is fit by both the RLM and HSM, but for widely differing temperatures, neither of which seems probable. The precise fitting of the observed S(1) line profile to computed models depends critically on the determination of the true continuum level; difficulties encountered in finding the continuum, especially for Jupiter, are discussed. Derived RLM densities and abundances for both planets are substantially lower than those derived from RLM analyses of the H2 quadrupole lines, the 3ν3 band of CH4, and from other sources.  相似文献   

20.
Gosain  Sanjay  Prasad Choudhary  Debi 《Solar physics》2003,217(1):119-132
Simultaneous observations of Stokes profiles in photospheric Fei (630.15 nm and 630.25 nm) and chromospheric Mgi b 1 and b 2 (518.4 nm and 517.3 nm) lines over a sunspot are presented. Observations were carried out using the Advanced Stokes Polarimeter of HAO/NSO, VTT, SacPeak, U.S.A. The Stokes-V amplitude asymmetries for these lines are analyzed. The values of amplitude asymmetry in Mgb lines are negative in disk-center-side penumbra while they are positive in limb-side penumbra. This trend is similar in nature to photospheric Fei line observations. Further, the spatial distribution of Stokes-V asymmetry is analyzed using Net Circular Polarization (NCP) maps. The chromospheric and photospheric NCP maps are different in many aspects. These observations with longitudinal magnetic field, estimated using weak field approximation, are discussed in this paper.  相似文献   

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