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1.
We study the variability of the Hγ, Hβ, and Hα line profiles in the spectrum of the supergiant κ Cas. The variability pattern proved to be the same for all the lines considered: their profiles are superimposed by blueshifted, central, and redshifted emission. For Hγ the positions of the emissions coincide with the positions of the corresponding emissions for He I λλ 5876, 6678 Å lines, and are equal to about ?135 ± 30.0 km s?1, ?20 ± 20 kms?1, and 135 ± 30.0 kms?1, respectively, whereas the three emissions in the Hβ profiles are fixed at about ?170.0 ± 70.0 kms?1, 20 ± 30 kms?1, and 170.0 ± 70.0 km s?1, respectively. The positions of the blueshifted and central emissions for Hα are the same as for Hβ, with additional blueshifted emission at ?135.0 ± 30.0 kms?1, whereas no traces of emission can be seen in the red wing of the line. These emissions show up more conspicuously in wind lines, however, their traces can be seen in all photospheric lines. When passing from wind lines to photospheric lines the intensity of superimposed emission components decreases and the same is true for the absolute values of their positions in line wings expressed in terms of radial velocities. The V/R variations of the lines studied found in the spectrum of κ Cas and the variability of the Hα emission indicate that the star is a supergiant showing Be phenomenon.  相似文献   

2.
Temporal variations of radial velocities and line profiles in the spectrum of the supergiant κ Cas were investigated. Variability of radial velocities and profiles of photospheric lines Si III, OII, He I, H10–Hδ and wind lines He I λ 5875, 6678 Å ismainly caused by non-radial pulsations. For photospheric lines quasisinusoidal variabilities of the radial velocity were found. Temporal variability of radial velocity of the wind lines He I λ 5875, 6678 A? differ from each other and from the photospheric lines. Gamma velocities and amplitudes of radial velocity variability were determined. The amplitude of variability and the velocity of expansion increase from lower to upper layers of the atmosphere. Emission components are superimposed on the line profiles at positions about ?135 ± 10.0, ?20 ± 20 and 135 ± 10.0 kms?1 respectively. They are more obvious in the wind line profiles, although, there are signs of emissions also in the photospheric lines. Such a character of variability of all the lines in the κ Cas spectrum confirms its Be nature.  相似文献   

3.
Based on our high-spectral-resolution observations performed with the NES echelle spectrograph of the 6-m telescope, we have studied the peculiarities of the spectrum and the velocity field in the atmosphere and envelope of the cool supergiant V1027 Cyg, the optical counterpart of the infrared source IRAS 20004+2955. A splitting of the cores of strong absorptions of metals and their ions (Si II, Ni I, Ti I, Ti II, Sc II, Cr I, Fe I, Fe II, BaII) has been detected in the stellar spectrum for the first time. The broad profile of these lines contains a stable weak emission in the core whose position may be considered as the systematic velocity V sys = 5.5 km s?1. Small radial velocity variations with an amplitude of 5–6 km s?1 due to pulsations have been revealed by symmetric low- and moderate-intensity absorptions. A long-wavelength shift of the Hα profile due to line core distortion is observed in the stellar spectrum. Numerous weak CN molecular lines and the KI 7696 Å line with a P Cyg profile have been identified in the red spectral region. The coincidence of the radial velocities measured from symmetric metal absorptions and CN lines suggests that the CN spectrum is formed in the stellar atmosphere. We have identified numerous diffuse interstellar bands (DIBs) whose positions in the spectrum, V r (DIBs) = ?12.0 km s?1, correspond to the velocity of the interstellar medium in the Local Arm of the Galaxy.  相似文献   

4.
Based on the high spectral resolution monitoring conducted at the 6-m BTA telescope, we study the optical spectrum of the high-latitude variable V534 Lyr. Heliocentric radial velocities Vr corresponding to the positions of all metal absorption components, as well as the Na I D and Hα lines were measured during all the observational sets. The analysis of the velocity field examining the lines of various nature revealed a low-amplitude variability of Vr based on the lines with a high excitation potential, which are formed in deep layers of the stellar atmosphere, and allowed to estimate the systemic velocity of Vsys ≈ ?125 kms?1 (Vlsr ≈ ?105 kms?1). The distance estimate of d ≈ 6 kpc for the star leads to its absolute magnitude of \(M_V \approx - 5_ \cdot ^m 3\), what corresponds to the spectral classification. The previously undetected spectral phenomenon was revealed for this star: at certain times a splitting of the profiles of low-excited absorptions is observed, reaching ΔVr = 20–50 kms?1. A combination of the parameters: reduced metallicity [Met/H] = ?0.28, high nitrogen abundance [N/Fe] = +1.10, large spatial velocity, high luminosity, a strong variability of the emission-absorption profiles of HI lines, splitting of metal absorptions at different times of observations and the variability of the velocity field in the atmosphere allow to classify V534 Lyr as a pulsating star in the thick disk of our Galaxy.  相似文献   

5.
We have selected and analyzed a sample of OB stars with known line-of-sight velocities determined through ground-based observations and with trigonometric parallaxes and propermotions from the Gaia DR2 catalogue. Some of the stars in our sample have distance estimates made from calcium lines. A direct comparison with the trigonometric distance scale has shown that the calcium distance scale should be reduced by 13%. The following parameters of the Galactic rotation curve have been determined from 495 OB stars with relative parallax errors less than 30%: (U, V,W) = (8.16, 11.19, 8.55)± (0.48, 0.56, 0.48) km s?1, Ω0 = 28.92 ± 0.39 km s?1 kpc?1, Ω'0 = ?4.087 ± 0.083 km s?1 kpc?2, and Ω″ 0 = 0.703 ± 0.067 km s?1 kpc?3, where the circular velocity of the local standard of rest is V0 = 231 ± 5 km s?1 (for the adopted R0 = 8.0 ± 0.15 kpc). The parameters of the Galactic spiral density wave have been found from the series of radial, VR, residual tangential, ΔVcirc, and vertical, W, velocities of OB stars by applying a periodogram analysis. The amplitudes of the radial, tangential, and vertical velocity perturbations are fR = 7.1± 0.3 km s?1, fθ = 6.5 ± 0.4 km s?1, and fW = 4.8± 0.8 km s?1, respectively; the perturbation wavelengths are λR = 3.3 ± 0.1 kpc, λθ = 2.3 ± 0.2 kpc, and λW = 2.6 ± 0.5 kpc; and the Sun’s radial phase in the spiral density wave is (χ)R = ?135? ± 5?, (χ)θ = ?123? ± 8?, and (χ)W = ?132? ± 21? for the adopted four-armed spiral pattern.  相似文献   

6.
A sample of classical Cepheids with known distances and line-of-sight velocities has been supplemented with proper motions from the Gaia DR1 catalogue. Based on the velocities of 260 stars, we have found the components of the peculiar solar velocity vector (U, V, W) = (7.90, 11.73, 7.39) ± (0.65, 0.77, 0.62) km s?1 and the following parameters of the Galactic rotation curve: Ω0 = 28.84 ± 0.33 km s?1 kpc?1, Ω′0 = ?4.05 ± 0.10 km s?1 kpc?2, and Ω″0 = 0.805 ± 0.067 km s?1 kpc?3 for the adopted solar Galactocentric distance R 0 = 8 kpc; the linear rotation velocity of the local standard of rest is V 0 = 231 ± 6 km s?1.  相似文献   

7.
8.
We consider stars with radial velocities, proper motions, and distance estimates from the RAVE4 catalogue. Based on a sample of more than 145 000 stars at distances r < 0.5 kpc, we have found the following kinematic parameters: \({\left( {U,{\kern 1pt} V,{\kern 1pt} W} \right)_ \odot }\) = (9.12, 20.80, 7.66) ± (0.10, 0.10, 0.08) km s?1, Ω0 = 28.71 ± 0.63 km s?1 kpc?1, and Ω0 = ?4.28 ± 0.11 km s?1 kpc?2. This gives the linear rotation velocity V 0 = 230 ± 12 km s?1 (for the adopted R 0 = 8.0 ± 0.4 kpc) and the Oort constants A = 17.12 ± 0.45 km s?1 kpc?1 and B = ?11.60 ± 0.77 km s?1 kpc?1. The 2D velocity distributions in the UV, UW, and VW planes have been constructed using a local sample, r < 0.25 kpc, consisting of ~47 000 stars. A difference of the UV velocity distribution from the previously known ones constructed from a smaller amount of data has been revealed. It lies in the fact that our distribution has an extremely enhanced branch near the Wolf 630 peak. A previously unknown peak at (U, V) = (?96, ?10) km s?1 and a separate new feature in the Wolf 630 stream, with the coordinates of its center being (U, V) = (30, ?40) km s?1, have been detected.  相似文献   

9.
We consider two samples of OB stars with different distance scales that we have studied previously. The first and second samples consist of massive spectroscopic binaries with photometric distances and distances determined from interstellar calcium lines, respectively. The OB stars are located at heliocentric distances up to 7 kpc. We have identified them with the Gaia DR1 catalogue. Using the proper motions taken from the Gaia DR1 catalogue is shown to reduce the random errors in the Galactic rotation parameters compared to the previously known results. By analyzing the proper motions and parallaxes of 208 OB stars from the Gaia DR1 catalogue with a relative parallax error of less than 200%, we have found the following kinematic parameters: (U, V) = (8.67, 6.63)± (0.88, 0.98) km s?1, Ω0 = 27.35 ± 0.77 km s?1 kpc?1, Ω′0 = ?4.13 ± 0.13 km s?1 kpc?2, and Ω″0 = 0.672 ± 0.070 km s?1 kpc?3, the Oort constants are A = ?16.53 ± 0.52 km s?1 kpc?1 and B = 10.82 ± 0.93 km s?1 kpc?1, and the linear circular rotation velocity of the local standard of rest around the Galactic rotation axis is V 0 = 219 ± 8 km s?1 for the adopted R 0 = 8.0 ± 0.2 kpc. Based on the same stars, we have derived the rotation parameters only from their line-of-sight velocities. By comparing the estimated values of Ω′0, we have found the distance scale factor for the Gaia DR1 catalogue to be close to unity: 0.96. Based on 238 OB stars of the combined sample with photometric distances for the stars of the first sample and distances in the calcium distance scale for the stars of the second sample, line-of-sight velocities, and proper motions from the Gaia DR1 catalogue, we have found the following kinematic parameters: (U, V, W) = (8.19, 9.28, 8.79)± (0.74, 0.92, 0.74) km s?1, Ω0 = 31.53 ± 0.54 km s?1 kpc?1, Ω′0 = ?4.44 ± 0.12 km s?1 kpc?2, and Ω″0 = 0.706 ± 0.100 km s?1 kpc?3; here, A = ?17.77 ± 0.46 km s?1 kpc?1, B = 13.76 ± 0.71 km s?1 kpc?1, and V 0 = 252 ± 8 km s?1.  相似文献   

10.
Based on the material of multiple high-resolution R = 60 000 observations conducted on the 6-m telescope (BTA) of the Special Astrophysical Observatory in combination with the Nasmyth Echelle Spectrograph (NES), we closely studied the features of the optical spectrum of the star MWC17 with the B[e] phenomenon. In the wavelength interval of 4050–6750 Å, we identified numerous permitted and forbidden emissions, interstellar Na I lines, and diffuse interstellar bands (DIBs). Radial velocities were estimated from lines of different origin. As the systemic velocity, Vsys, the velocity of the forbidden emissions can be accepted: ?47 kms?1 (relative to the local standard Vlsr = ?42 kms?1). Comparison of the obtained data with the earlier measurements allows us to conclude on the absence of considerable variability of spectral details.  相似文献   

11.
We have studied the simultaneous and separate solutions of the basic kinematic equations obtained using the stellar velocities calculated on the basis of data from the Gaia TGAS and RAVE5 catalogues. By comparing the values of Ω'0 found by separately analyzing only the line-of-sight velocities of stars and only their proper motions, we have determined the distance scale correction factor p to be close to unity, 0.97 ± 0.04. Based on the proper motions of stars from the Gaia TGAS catalogue with relative trigonometric parallax errors less than 10% (they are at a mean distance of 226 pc), we have found the components of the group velocity vector for the sample stars relative to the Sun (U, V,W) = (9.28, 20.35, 7.36) ± (0.05, 0.07, 0.05) km s?1, the angular velocity of Galactic rotation Ω0 = 27.24 ± 0.30 km s?1 kpc?1, and its first derivative Ω'0 = ?3.77 ± 0.06 km s?1 kpc?2; here, the circular rotation velocity of the Sun around the Galactic center is V0 = 218 ± 6 km s?1 kpc (for the adopted distance R0 = 8.0 ± 0.2 kpc), while the Oort constants are A = 15.07 ± 0.25 km s?1 kpc?1 and B = ?12.17 ± 0.39 km s?1 kpc?1, p = 0.98 ± 0.08. The kinematics of Gaia TGAS stars with parallax errors more than 10% has been studied by invoking the distances from a paper by Astraatmadja and Bailer-Jones that were corrected for the Lutz–Kelker bias. We show that the second derivative of the angular velocity of Galactic rotation Ω'0 = 0.864 ± 0.021 km s?1 kpc?3 is well determined from stars at a mean distance of 537 pc. On the whole, we have found that the distances of stars from the Gaia TGAS catalogue calculated using their trigonometric parallaxes do not require any additional correction factor.  相似文献   

12.
We present the results of the reduction of our photometric and spectroscopic observations for the eclipsing binary SZ Cam performed with the telescopes at the Astronomical Observatory of the Ural Federal University and the Special Astrophysical Observatory of the Russian Academy of Sciences in 1996–2014. Based on an 11-year-long photometric monitoring of SZ Cam, we have obtained new elements of its photometric orbit and parameters of its components. We have detected low-amplitude periodic light variations in SZ Cam that are possibly related to the ellipsoidal shape of the components of the spectroscopic binary third body. Based on published data and our new spectroscopy, we have found new values for the mass ratio, q = 0.72 ± 0.01, and parameters of the radial velocity curves of the components, V 0 = ?3.6 ± 1.7 km s?1, K 1 = 190.2 ± 1.9 km s?1, and K 2 = 263.0 ± 2.4 km s?1. The component masses have been estimated to be M 1 = 16.1 M and M 2 = 11.6 M . We have obtained new light elements and parameters of the radial velocity curves for the third body, V 0 3b = 4.2 ± 0.6 km s?1 and K 1 3b = 26.6 ± 0.8 km s?1. We have improved the period of the relative orbit of SZ Cam and the third body, P orb = 55.6 ± 1.5 yr.  相似文献   

13.
Open star clusters from the MWSC (Milky Way Star Clusters) catalogue have been used to determine the Galactic rotation parameters. The circular rotation velocity of the solar neighborhood around the Galactic center has been found from data on more than 2000 clusters of various ages to be V 0 = 236 ± 6 km s?1 for the adopted Galactocentric distance of the Sun R 0 = 8.3 ± 0.2 kpc. The derived angular velocity parameters are Ω 0 = 28.48 ± 0.36 km s?1 kpc?1, Ω0 = ?3.50 ± 0.08 km s?1 kpc?2, and Ω0 = 0.331 ± 0.037 km s?1 kpc?3. The influence of the spiral density wave has been detected only in the sample of clusters younger than 50 Myr. For these clusters the amplitudes of the tangential and radial velocity perturbations are f θ = 5.6 ± 1.6 km s?1 and f R = 7.7 ± 1.4 km s?1, respectively; the perturbation wavelengths are λ θ = 2.6 ± 0.5 kpc (i θ = ?11? ± 2?) and λ R = 2.1 ± 0.5 kpc (i R = ?9? ± 2?) for the adopted four-armed model (m = 4). The Sun’s phase in the spiral density wave is (χ)θ = ?62? ± 9? and (χ)R = ?85? ± 10? from the residual tangential and radial velocities, respectively.  相似文献   

14.
15.
Strong (“kilogauss”) small-scale magnetic fields were detected outside a sunspot near the seismic source of the major X17.2/4B solar flare on October 28, 2003. Echelle Zeeman spectrograms of the flare were obtained with the horizontal solar telescope at the Astronomical Observatory of the Taras Shevchenko Kiev National University. Analysis of the Stokes I ± V profiles for the Fe I 5232.9, 5247.1, 5250.2, and 5397.1 Å lines has revealed a number of characteristic spectral features. These are indicative of both background fields with a strength of ≈300 G and small-scale fields with a strength of 1300–3100 G. Evidence for the presence of another small-scale field component of opposite polarity with a strength of 8–10 kG has been found. A redshift (downflow) with a velocity of 1 km s?1 was observed in the latter component.  相似文献   

16.
We measured the radial velocity of the star θ1 Ori D from IUE spectra and used published observations. Based on these data, we determined the period of its radial-velocity variations, P=20.2675±0.0010 days, constructed the phase radial-velocity curve, and solved it by least squares. The spectroscopic orbital elements were found to be the following: the epoch of periastron passage Ep=JD 2430826.6±0.1, the system's center-of-mass velocity /Gg=32.4±1.0 km s?1, K=14.3±1.5 km s?1, Ω=3.3±0.1 rad, e=0.68±0.09, a1 sin i = 3 × 1010 km, and f1 = 0.0025M. Twice the period, P=40.528±0.002 days, is also consistent with the observations.  相似文献   

17.
We present LTE analysis of high resolution optical spectra for B-type hot PAGB stars LS IV-04 1 and LB3116 (LSE 237). The spectra of these high Galactic latitude stars were obtained with the 3.9-m Anglo-Australian Telescope (AAT) and the UCLES spectrograph. The standard 1D LTE analysis with line-blanketed LTE model atmospheres and spectral synthesis provided fundamental atmospheric parameters of Teff= 15 000±1000 K, log g= 2.5±0.2, ξ = 5.0±1.0 km s?1, [M/H] = ?1.81 dex, and v sin i= 5 km s?1 for LSIV-04 1 and Teff= 16 000±1000 K, log g= 2.5±0.1, v sin i= 25 km s?1, and [Fe/H] = ?0.93 dex for LB 3116. Chemical abundances of ten different elements were obtained. For LS IV-04 1, its derived model temperature contradicts with previous analysis results. The upper limits for its nitrogen and oxygen abundances were reported for the first time. The magnesium, silicon and calcium were overabundant (i.e. [Mg/Fe] = 0.8 dex, [Si/Fe] = 0.5 dex, [Ca/Fe] = 0.9 dex). With its metal-poor photosphere and VLSR ≈ 96 km s?1, LSIV-04 1 is likely a population II star and most probably a PAGB star. LTE abundances of LB 3116 were reported for the first time. The spectrum of this helium rich star shows 0.9 dex enhancement in the nitrogen. The photosphere of the star is slightly deficient in Mg, Si, and S. (i.e. [Mg/Fe] = ?0.2 dex, [Si/Fe] = ?0.4 dex, [S/Fe] = ?0.2 dex). The Al is slightly enhanced. The phosphorus is overabundant, i.e. [P/Fe] ≈ 1.7 ± 0.47 dex, hence LB3116 may be the first example of a PAGB star which is rich in phosphorus. With its high radial velocity (i.e.VLSR = 73 km s?1), and the deficiencies observed in C, Mg, Si, and S indicate that LB 3116 is likely a hot PAGB star at high galactic latitude.  相似文献   

18.
Spectra of an Ellerman bomb in the NOAA 11024 active region were obtained in spectropolarimetric observations with the French–Italian THEMIS telescope (Tenerife, Spain). The variations of profiles of the Stokes parameters I, Q, U, and V of photospheric lines were analyzed. The chosen lines had different intensities and magnetic-field sensitivities. It was found that the photospheric line profiles in the Ellerman bomb spectra differed greatly from the profiles for the quiet photosphere outside the active region. The Stokes I profiles of photospheric lines in the Ellerman bomb spectra were much weaker. The largest values of the Stokes parameters Q, U, and V were derived for the Fe I λ 630.25 nm magnetosensitive line. The Stokes parameter V was the highest in the central region of the Ellerman bomb, while the maximum Q and U parameters were observed at one of the edges of the Ellerman bomb. It follows from the comparison of the Stokes parameters for the Ellerman bomb and microflares that the Q, U, and V parameters for the bomb are much higher than those for flares.  相似文献   

19.
Repeated spectroscopic observations made with the 6-m telescope of SAO RAS yielded new data on the radial-velocity variability of the anomalous yellow supergiant QY Sge. The strongest and most peculiar feature in its spectrum is the complex profile of NaI D lines, which contains a narrow and a very wide emission components. The wide emission component can be seen to extend from ?170 to +120 km/s, and at its central part it is cut by an absorption feature, which, in turn, is split into two subcomponents by a narrow (16 km/s at r=2.5) emission peak. An analysis of all the Vr values leads us to adopt for the star a systemic velocity of Vr=?21.1 km/s, which corresponds to the position of the narrow emission component of NaI. The locations of emission-line features of NaI D lines are invariable, which point to their formation in regions that are external to the supergiant’s photosphere. Differential line shifts of about 10 km/s are revealed. Emission in the Hα line is weaker than in NaI D lines, it fills the photospheric absorption almost completely. The absorption lines in the spectrum of QY Sge have a substantial width of FWHM ≈ 45 km/s. The method of model atmospheres is used to determine the following parameters: the effective temperature T eff =6250±150 K, surface gravity l g g=2.0±0.2, and microturbulence velocity ξ t =4.5±0.5 km/s. The chemical composition of the atmosphere differs only slightly from the solar composition: the metallicity of the star is found to be somewhat higher than the solar metallicity with an average overabundance of iron-peak elements of [Met/H]=+0.20. The star is found to be slightly overabundant in carbon and nitrogen, [C/Fe]=+0.25, [N/Fe]=+0.27. The α-process elements Mg, Si, and Ca are slightly overabundant, on the average by [α/H]=+0.12, and sulfur overabundance is higher, [S/α]=+0.29. The strong overabundance of sodium, [Na/Fe]=+0.75, is likely to be due to the dredge-up of the matter processed in the NeNa cycle. Heavy elements of the s-process are underabundant relative to the Sun. On the whole, the observed properties of QY Sge do not give grounds for including this star into the group of RCrB or RVTau-type objects.  相似文献   

20.
The T Tauri variable V1331 Cyg is characterized by an intensive emission spectrum, by signatures of a high rate of mass loss, and also by presence of a circular reflection nebula. According to these characteristics, the star can be considered as a possible pre-FUor star. Up to the present the photospheric spectrum of the star has not been recorded. In this work we analyze the high-resolution spectra of V1331 Cyg that were obtained by G.H. Herbig with the HIRES spectrograph at the Keck-1 telescope in 2004 and 2007. For the first time the numerous photospheric lines of the star have been detected and the spectral class has been estimated, viz., G7-K0 IV. It is revealed that the projection of the rotation velocity is lower than the width of instrumental profile (vsini < 6 km/s); this means that the angle between the stellar axis of rotation and the line of sight is small. The radial velocity of the star derived from the photospheric lines is RV = ?15.0 ± 0.3 km/s. The difference in radial velocities for 2004 and 2007 is lower than the measurement error. The photospheric spectrum is veiled considerably, but the amount of veiling is not the same in different lines. This depends on the line strength in the template spectrum of the G7 IV star: in the weakest lines (EW = 5–10 mÅ in the template spectrum) VF ≈ 1 and it increases up to 4–5 in stronger lines. The Hα and Hβ lines demonstrate classical P Cyg profiles, which testifies to an intensive wind with a maximal velocity of about 400 km/s. In addition, the emission lines of Fe II, Mg I and K I and of several other elements are accompanied by a narrow blue-shifted absorption at ?150...?250 km/s. The emission spectrum of V1331 Cyg is rich in the narrow (FWHM = 30–50 km/s) lines of neutral and ionized metals showing the excitation temperature T exc = 3800 ± 300 K. The stellar mass M* ≈ 2.8M and radius R* ≈ 5R are estimated.  相似文献   

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