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High-resolution spectra of the LBV candidate Schulte 12 in the Cyg OB2 association were obtained at the 6-meter BTA telescope with the NES echelle spectrograph on the arbitrary dates in 2001-2022. Variability of the emission profile of H$\alpha$ and absorptions of HeI, SiII with time was found. Based on the radial velocity measurements at 10 observation dates, radial velocity variability with an amplitude of $\Delta$Vr$\approx$8 km/s relative to the average value of the heliocentric velocity Vr=$-15.6\pm2.6$ km/s was revealed. This indicates the presence of a companion in the system. Based on the reliable intensity measurements of a sample of DIBs, color excess E(B-V)=1.74$\pm0.03^{m}$ was determined. This results in the interstellar extinction value Av$\approx 5.6^m$ that is only about half of the total extinction. Taking current Schulte 12 parameters, including Gaia~EDR3 parallax, we estimated its absolute magnitude as Mv$\approx -9.2^m$ and luminosity log$(L/L_{\odot})\approx$5.5, which does not exceed the Humphreys-Davidson limit., Comment: 14 pages, 3 tables, 5 figures, accepted by Astronomy Reports

In the optical spectra of the cold post-AGB supergiant GSC 04050$-$02366, obtained with the 6-meter BTA telescope with a spectral resolution of R$\ge$60000 on arbitrary dates over 2019$\div$2021, a radial velocity variability is found. Heliocentric Vr based on the positional measurements of numerous absorptions varies from date to date with a standard deviation of $\Delta$Vr$\approx$1.4 km/s about the average value of Vr=24.75 km/s, which may stem out of the low-amplitude pulsations in the atmosphere. The spectra of the star are purely absorption type, there are no obvious emissions. Intensity variability of most of absorptions and Swan bands of the C$_2$ molecule was discovered. A slight asymmetry of the H$\alpha$ profile is observed at some observation dates. The position of H$\alpha$ absorption core varies within 27.3$\div$30.6 km/s. Splitting into two components (or asymmetry) of strong low-excitation absorptions (YII, ZrII, BaII, LaII, CeII, NdII) was found. The position of the long-wavelength component coincides with the position of other photospheric absorptions, which confirms its formation in the atmosphere of the star. The position of the shortwave component is close to the position of the rotational features of Swan bands, which indicates its formation in the circumstellar envelope expanding at a velocity of about Vexp=16 km/s., Comment: 9 pages, 5 figures. 2 tables

The optical spectra of the B-supergiant LS III+52 24 (IRAS 22023+5249) obtained at the 6-meter telescope BTA with a resolution R$\ge$60000 in 2010-2021 revealed signs of wind variability and velocity stratification in the extended atmosphere. The H$\alpha$ and H$\beta$ lines have a P Cyg type profile; their wind absorption changes position in the range from $-270$ to $-290$ km/s. The intensity of the H$\alpha$ emission reaches record values with respect to the local continuum: I/Icont $\approx$70. The stationary radial velocity according to the positions of symmetric forbidden emissions and permitted metal emissions was taken as the systemic velocity Vsys=$-149.6\pm$0.6 km/s. Based on the positions of absorptions of NII and OII ions, a time variability of the radial velocity in the range from $-127.2$ to $-178.3$ km/s was found for the first time for this star. This variability indicates the possible presence of a companion and/or atmospheric pulsations. The change of the oxygen triplet profile OI 7775 A due to the occurrence of unstable emission was registered. The set of interstellar absorptions of the NaI D-lines profile in the range from $-10.0$ to $-167.2$ km/s is formed in the Local Arm and subsequent arms of the Galaxy. The distance to the star, d$\ge$5.3 kpc, combined with the high systemic velocity, indicates that the star is located in the Galaxy beyond the Scutum-Crux arm., Comment: 10 pages, 7 figures, accepted to Astronomy Reports

Over the past two decades the echelle spectrograph NES of the 6-m telescope was used to perform high resolution spectroscopy of far evolved stars spanning a wide range of initial masses. The studies cover a diversity of stars with high mass-loss rates during the preceding and current stages of evolution. All these stars have extended atmospheres and structured circumstellar envelopes produced by strong stellar winds. We have studied luminous blue variables near the Eddington limit; hot supergiants with B[e] phenomenon in spectra, which are very likely intermediate-mass binary systems soon after the fast mass exchange stage; a group of yellow hypergiants, as well as an extensive sample of low-mass post-AGB supergiants. The diverse nature of the types of these stars whose common feature is the presence of a circumstellar envelope makes the spectroscopy of such objects a comprehensive task. Such studies consist of many etapes, which include not only determining the peculiarities of their atmospheric chemical composition and understanding the role of supergiants in the enrichment of the interstellar medium with freshly synthesized elements, but also the determination of the evolution status of the objects considered, as well as search for and analysis of spectroscopic manifestations of kinematic processes in their extended and unstable atmospheres and gas-dust envelopes. We spectroscopically monitored selected objects to study in detail the instability of the kinematic state of the atmospheres of the stars considered. This review reports briefly the most significant observational obtained within the framework of the programs in 1998--2021., Comment: 10 pages, 8 figures

We briefly present the history of technical solutions aimed at improving the efficiency of spectroscopy on small- and moderate-diameter telescopes. We assess the current state of spectroscopy techniques and some of the perspectives., Comment: 36 pages, 2 tables, 199 references, will be published in Astrophysical Bulletin, vol 76, No 2, 2021

Some evidences of wind variability and velocity stratification in the extended atmosphere has been found in the spectra of the supergiant V340 Ser (=IRAS 17279$-$1119) taken at the 6-m BTA telescope with a spectral resolution R$\ge$60000. The H$\alpha$ line has a P Cyg profile whose absorption component (V=+34 km/s) is formed in the upper layers of the expanding atmosphere close to the circumstellar environment. For four dates the mean velocity has been derived from the positions of 300-550 symmetric metal absorptions with an accuracy better than $\pm0.1$ km/s: Vr=59.30, 60.09, 58.46, and 55.78 km/s. A lot of low-excitation metal lines have an inverse P Cyg profile. The mean positions of their emission components, Vr=46.3$\pm$0.4 km/s, differ systematically from the velocity inferred from symmetric absorptions, suggesting the presence of a velocity gradient in the supergiant extended atmosphere. The multicomponent profile of the NaI D-lines contains the interstellar, Vr=-11.2 km/s, and circumstellar, Vr=+10 km/s, components and the component forming in the upper atmospheric layers, Vr=+34.0 km/s. The mean velocity from 20-30 diffuse interstellar bands (DIBs) identified in the spectra, Vr(DIBs)=-11.6$\pm0.2$ km/s, agrees with the velocity from interstellar NaI and KI components. The equivalent width of the oxygen triplet W(7774)=1.25 A corresponds to an absolute magnitude of the star Mv$\approx-4.6^m$, which, taking into account the total (interstellar+circumstellar) extinction, leads to a distance to the star d$\approx$2.3 kpc., Comment: 17 pages, 6 figures

We report the results of a long-term spectroscopic monitoring of the A-type supergiant with the B[e] phenomenon 3 Pup = HD 62623. We confirm earlier findings that it is a binary system. The orbital parameters were derived using cross-correlation of the spectra in a range of 4460-4632 A, which contains over 30 absorption lines. The orbit was found circular with a period of $137.4\pm0.1$ days, radial velocity semi-amplitude $K_{1} = 5.0\pm0.8$ km s$^{-1}$, systemic radial velocity $\gamma = +26.4\pm2.0$ km s$^{-1}$, and the mass function $f(m) = (1.81^{+0.97}_{-0.76})\times10^{-3}$ M$_{\odot}$. The object may have evolved from a pair with initial masses of $\sim$6.0 M$_{\odot}$ and $\sim$3.6 M$_{\odot}$ with an initial orbital period of $\sim$5 days. Based on the fundamental parameters of the A-supergiant (luminosity $\log$ L/L$_{\odot} = 4.1\pm$0.1 and effective temperature T$_{\rm eff} = 8500\pm$500 K) and evolutionary tracks of mass-transferring binaries, we found current masses of the gainer M$_{2} = 8.8\pm$0.5 M$_{\odot}$ and donor M$_{1} = 0.75\pm0.25$ M$_{\odot}$. We also modeled the object's IR-excess and derived a dust mass of $\sim 5\,\times10^{-5}$ M$_{\odot}$ in the optically-thin dusty disk. The orbital parameters and properties of the H$\alpha$ line profile suggest that the circumstellar gaseous disk is predominantly circumbinary. The relatively low mass of the gainer led us to a suggestion that 3 Pup should be excluded from the B[e] supergiant group and moved to the FS CMa group. Overall these results further support our original suggestion that FS CMa objects are binary systems, where an earlier mass-transfer caused formation of the circumstellar envelope., Comment: 13 pages, 9 figures, 4 tables, accepted in The Astrophysical Journal

We summarize the results of long-term spectral monitoring of yellow hypergiants (YHGs) of northern hemisphere with a R$\ge$60000 resolution. The spectra of these F-G stars of extremely high luminosity, compactly located at the top of the Hertzsprung-Russell diagram revealed a variety of spectral features: various types of H$\alpha$ profile, the presence (or absence) of forbidden and permitted emissions, as well as circumstellar components. Variability of spectral details of various nature is studied. Absolute luminosity, circumstellar envelope expansion rate and amplitude of pulsations are determined. The reliability of the YHG status for V1427 Aql is reliably confirmed; manifestations of a significant dynamic instability of the upper layers of the atmosphere of $\rho$ Cas after the 2017 ejection and stratification of its gas envelope are registered; the lack of companion in the system of the V509 Cas hypergiant is proven; a conclusion is made that the V1302 Aql hypergiant is approaching to the low-temperature boundary of the Yellow Void., Comment: 24 pages, 10 figures

An optical spectrum of the star V1648 Aql (=IRAS 19386+0155) was obtained at the 6-meter telescope with a spectral resolution of R$\ge$60\,000. Heliocentric radial velocity measured from numerous metallic absorptions is equal to V$_r$=$10.18\pm0.05$ km s$^{-1}$ (V$_{\rm LSR}$=18.1 km s$^{-1}$). We determined the atmospheric, circumstellar, and interstellar components in the profile of the NaI D~lines at V$_r$=9.2, $-3.4$, and $-12.8$ km s$^{-1}$ respectively. The averaged over twenty identified DIBs velocity V$_r$(DIBs)=$-12.5\pm0.2$ km~s$^{-1}$ coincides with the interstellar NaI component. Weak emissions with an intensity of about 10% of the local continuum level were detected in the spectrum; they are identified as low-excitation metal lines. Their averaged position, V$_r$=$8.44\pm0.28$ km s$^{-1}$, may point to the presence of a weak velocity gradient in the upper layers of the stellar atmosphere. Based on the spectroscopic data and taking into account the interstellar and circumstellar reddening, we estimated the star's luminosity M$_V\approx-5^{\rm m}$ and also obtained the lower estimate of distance d$\ge1.8$ kpc. Using the model atmosphere method, we determined the fundamental parameters and chemical abundances in the atmosphere approving the status of a post-AGB star for V1648 Aql., Comment: 16 pages, 4 figures, 4 tables

The results of our second stage (1998-2018) of the detailed spectroscopy of peculiar supergiants identified with galactic infrared sources, performed mainly at the 6-meter BTA telescope are summarized. The main aspect of the program is a search for the evolutionary variations in the chemical composition of stars, past the AGB stage and the TDU, as well as an analysis of spectral manifestations of kinematic processes in their extended, often unstable, atmospheres and in the envelopes. The most significant result is detection of the s-process element excesses in seven single post-AGB stars, which confirms the theory of evolution of this type of stars. In three of these stars we for the first time discovered the ejection of the s-process heavy metals to the circumstellar envelopes. A lithium excess was found in the atmospheres of two peculiar supergiants V2324 Cyg and V4334 Sgr. The results of investigation of the kinematical state of atmospheres and envelopes will clarify the equilibrium of matter produced by stars in the AGB and post-AGB stages and delivered to the interstellar medium., Comment: 35 pages, 10 figures

Based on the data of spectral monitoring of the yellow hypergiant V509 Cas performed in 1996-2018 at the 6-m telescope with the spectral resolution of R$\ge$60 000, we studied in detail its kinematic state at various levels of extended atmosphere. No signs of presence of a companion were found. An agreement of radial velocities measured on the permitted and forbidden emissions of metal ions, as well as their strict temporal stability led us to the choice of the systemic velocity of the star Vsys=$-63$ km/s. The position of forbidden [NII] emissions forming in the circumstellar medium is strictly stable and is systematically shifted by $-6$ km/s relative to the metal ion emissions. A conclusion on the variation of the [NII] emission halfwidths and intensities (the lines have become narrower and more intense) is made after the observations in 1996 and these parameters did not vary over the next 22 years of observations. The velocities measured from the shortwave FeII(42) absorption components are located in a narrow interval of Vr=$-$(84$\div$87) km/s, which indicates the stability of expansion of the upper layers of the atmosphere. The overall atmosphere of the hypergiant is stable, excluding the layers close to the photosphere. The velocity variability in range of Vr=$-$(52$\div$71) km/s, identified by the positions of strong metal ion absorption cores, may be a manifestation of pulsations in deep atmospheric layers, where this type of lines are formed., Comment: 18 pages, 5 figures, 3 tables

Spectral monitoring of the yellow hypergiant $\rho$ Cas with the by 6-m telescope of the Special Astrophysical Observatory with a spectral resolution of R$\ge$60000 has led to the detection of new features in the kinematic state of its extended atmosphere following the ejection of matter in 2013. Significant changes in the profile of the H$\alpha$ line were detected: the line had a doubled core for the first time in a 2014 spectrum, an inverse P Cygni profile on December 13, 2017, and the profile was again doubled on August 6, 2017 and September 5, 2017, but its core was strongly shifted toward longer wavelengths, indicating a rapid infall of matter. Splitting of the profiles of strong, low-excitation absorptions into three components was first detected in 2017. There is no correlation between the evolution of the profiles of H$\alpha$ and the splitted absorptions. Pulsation-like variability with an amplitude of about 10 km/s is characteristic only of symmetric weak and moderate-intensity absorption lines. Shell emissions of iron-group elements can be identified in the long-wavelength part of a spectrum obtained in 2013, whose intensity decreased until they completely disappeared in 2017. In the absence of emission in the cores of the H and K lines of CaII, emissions of shell metals are visible in the wings of these lines., Comment: 15 pages, 6 figures

Based on the high resolution spectral 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 NaI D and H$\alpha$ lines were measured during all the observational dates. 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$\approx-125$ km/s (V(lsr)$\approx-105$ km/s). The distance estimate of d$\approx$6 kpc for the star leads us to its absolute magnitude of Mv$\approx -5.3^{m}$, what corresponds to the MK spectral classification. The previously undetected for this star spectral phenomenon was revealed: at certain times a splitting of the profiles of low-excited absorptions is observed, reaching $\Delta$Vr=20$\div$50 km/s. A combination of the parameters: reduced metallicity [Met/H]$_{\odot}=-0.28$, increased 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 observation moments and the variability of the velocity field in the atmosphere allow us to consider V534 Lyr as a pulsating star in the instability band near the HB and belonging to the thick disk of our Galaxy., Comment: 21 pages, 7 figures, 4 tables

The phenomenon of spectral mimicry refers to the fact that hypergiants and post-AGB supergiants - stars of different masses in fundamentally different stages of their evolution have similar optical spectra, and also share certain other characteristics (unstable and extended atmospheres, expanding gas-dust envelopes, high IR excesses). As a consequence, it is not always possible to distinguish post-AGB stars from hypergiants based on individual spectral observations in the optical range. Examples of spectral mimicry are presented using uniform, high-quality spectral material obtained on the 6-m telescope of the Special Astrophysical Observatory in the course of long-term monitoring of high-luminosity stars. It is shown that unambiguously resolving the mimicry problem for individual stars requires the determination of a whole set of parameters: luminosity, wind parameters, spectral energy distribution, spectral features, velocity field in the atmosphere and circumstellar medium, behavior of the parameters with time, and the abundances of chemical elements in the atmosphere., Comment: 17 pages, 7 figures, 1 table

For the first time, based on long-term spectral monitoring with high spectral resolution, the optical spectrum of the weak central star of the IR source RAFGL 5081 has been studied. The spectral type of this star is close to G5-8 II, and its effective temperature is Teff ~5400 K. An unusual spectral phenomenon was discovered: splitting of the profiles of broad, stationary absorption lines of medium and low intensity. The heliocentric radial velocities Vr of all components of metal absorption lines, the NaI D lines, and the H$\alpha$ line were measured for all the observation epochs. The constancy of the absorption lines rules out the possibility that the line splitting is due to binarity. The radial velocities of the wind components in the profiles of the NaI D and H$\alpha$ lines reach $-250$ and $-600$ km/s, respectively. These profiles have narrow components, whose number, depth, and position vary with time. The time variability and multicomponent structure of the profiles of the NaI D and H$\alpha$ lines indicates inhomogeneity and instability of the circumstellar envelope of RAFGL 5081. The presence of components with velocity Vr(IS)=$-65$ km/s in the NaI(1) lines provides evidence that RAFGL 5081 is located behind the Perseus arm, i.e., no closer than 2 kpc. It is noted that RAFGL 5081 is associated with the reflection nebula GN 02.44.7., Comment: 18 pages, 2 tables, 6 figures

Observational manifestations of far evolved stars at the asymptotic giants branch and their nearest descendants are briefly considered. Main results of their chemical composition determinations based on long term high resolution spectroscopy at the 6-m telescope are also briefly summed up. A new kind of peculiarity of optical spectra is found and discussed: splitting or asymmetry of strongest absorptions in the optical spectra of selected post-AGB stars with envelopes and atmospheres enriched in carbon and s-process heavy metals., Comment: 7 pages, 1 figure, 1 table, to publish in the proceedings of the conference "Stars: from collapse to collapse", SAO RAS, Nizhnij Arkhyz, Russia, 3-7 October 2016

Based on high-resolution spectroscopy 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. For the first time, a splitting of the cores of strong absorptions of metals and their ions (SiII, NiI, TiI, TiII, ScII, CrI, FeI, FeII, BaII) has been detected in the stellar spectrum. The broad profile of these lines contains a stable weak emission in the core whose position may be considered as the systematic velocity Vsys=5.5 km/s. Small radial velocity variations with an amplitude of 5-6 km/s due to pulsations have been revealed by symmetric low- and moderate-intensity absorptions. A long-wavelength shift of the H$\alpha$ profile due to line core distortion is observed in the stellar spectrum. Numerous weak CN molecular lines and the KI 7696 \AA\ 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 also identified numerous diffuse interstellar bands (DIBs) whose positions in the spectrum, Vr(DIBs)=$-12.0$ km/s, correspond to the velocity of the interstellar medium in the Local arm of the Galaxy., Comment: 15 pages, 6 figures, 2 tables

An atlas of spectra of the unique high luminosity objects MWC 314 and IRC+10420 taken with the CCD echelle spectrograph (R=15000) at the prime focus of the 6-m telescope of SAO is presented. About 320 emission and absorption features of stellar, circumstellar and interstellar nature are identified in the interval between 4790 and 7520 \AA{}. Their relative intensities and radial velocities are given and the distinctions of their profiles are discussed., Comment: 29 pages, 20 figures, 4 tables

Based on the data of multiple high-resolution R=60 000 observations obtained at the 6-meter telescope BTA in combination with the NES spectrograph, we studied the features of the optical spectrum of the star MWC 17 with the B[e] phenomenon. In the wavelength interval 4050-6750 A we identified numerous permitted and forbidden emissions, interstellar NaI lines, and diffuse interstellar bands (DIBs). Radial velocities were estimated from lines of various origin. As the systemic velocity, Vsys, the velocity from the forbidden emissions can be accepted: Vr=-47 km/s (relative to the local standard Vlsr=-42 km/s). Comparison of the obtained data with the ealier measurements allows us to conclude on the absence of considerable variability of spectral details., Comment: 14 pages, 2 figures, 5 tables

We present the results of the radial velocity ($RV$) measurements of metallic lines as well as H$_{\alpha}$ (H$_{\beta}$) obtained in 55 high-resolution spectra of the Cepheid $\alpha$ UMi (Polaris Aa) in 1994-2010. While the $RV$ amplitudes of these lines are roughly equal, their mean $RV$ begin to differ essentially with growth of the Polaris Aa pulsational activity. This difference is accompanied by the H$_{\alpha}$ line core asymmetries on the red side mainly (so-called knife-like profiles) and reaches 8-12 km/s in 2003 with a subsequent decrease to 1.5-2 km/s. We interpret a so unusual behaviour of the H$_{\alpha}$ line core as dynamical changes in the envelope around Polaris Aa., Comment: 5 pages, 6 figures, 1 table

A new type of peculiarity -- a splitting or asymmetry of strong absorption lines, is found in the optical spectra of selected post-AGB stars with C-rich circumstellar envelopes. The effect is maximal in BaII lines whose profile is split into two-three components. The particular components of the split absorption lines are shown to be formed in a structured circumstellar envelope, suggesting an efficient dredge-up of the heavy metals produced during the preceding evolution of this star into the envelope. We suspect that the splitting (or asymmetry) of the profiles of strongest absorptions with low excitation potential of the low level can be associated with the kinematic and chemical properties of the circumstellar environment and with type of its morphology., Comment: 14 pages, 2 tables, 4 fifures. arXiv admin note: substantial text overlap with arXiv:1408.0599

Based on high-spectral-resolution observations (R=60000) performed with the 6-m BTA telescope in combination with the echelle spectrograph NES, we have studied the optical spectra of three A-type supergiants: a peculiar supergiant 3 Pup, a post-AGB star BD+48 1220, and a massive $\alpha$ Cyg, which belong to essentially different stages of evolution. A spectral atlas for these stars is prepared in the wavelength interval of 3920 to 6720 \AA., Comment: 56 pages, 2 tables, 10 figures

Based on high-spectral resolution observations performed with the echelle spectrograph NES of the 6-meter telescope, we have studied the peculiarities of the spectrum and the velocity field in the atmosphere and envelope of the optical counterpart of the infrared source IRAS 23304+6347. We have concluded about the absence of significant variations in the radial velocity Vr inferred from atmospheric absorptions and about its coincidence with the systemic velocity deduced from radio data. The envelope expansion velocity Vexp=15.5 km/s has been determined from the positions of rotational band lines of the C$_2$ Swan (0; 0) band. A complex emission-absorption profile of the Swan (0; 1) 5635 \AA{} has been recorded. Analysis of the multicomponent NaI~D doublet line profile has revealed interstellar components V(IS)=$-61.6$ and $-13.2$ km/s as well as a circumstellar component with V(CS)=$-41.0$ km/s whose position corresponds to the velocity inferred from C$_2$ features. The presence of the interstellar component with Vr=$-61.6$ km/s in the spectrum allows d=2.5 kpc to be considered as a lower limit for the distance to the star. A splitting of the profiles for strong absorptions of ionized metals (YII, BaII, LaII, SiII) attributable to the presence of a short-wavelength component originating in the circumstellar envelope has been detected in the optical spectrum of IRAS23304+6347 for the first time., Comment: 14 pages, 2 figures, 1 Table

Highly-resolution optical spectra of the optical component of the IR-source IRAS01005+7910 are used to determine the spectral type of its central star, B1.5$ \pm $0.3, identify the spectral features, and analyze their profile and radial velocity variations. The systemic velocity Vsys =$-50.5$ km/s is determined from the positions of the symmetric and stable profiles of the forbidden [NI], [NII], [OI], [SII], and [FeII] emission lines. The presence of the [NII] and [SII] forbidden emissions indicates the onset of the ionization of the circumstellar envelope and the fact that the star is very close to undergoing the planetary nebula stage. The broad range of heliocentric radial velocity Vr estimates based on the core lines, which amounts to about 34 km/s, is partly due to the deformations of the profiles caused by variable emissions. The variations of the Vr in the line wings are smaller, about 23 km/s, and may be due to pulsations and/or hidden binarity of the star. The deformations of the profiles of complex absorption-emission lines may result from variations of their absorption components caused by the variations of the geometry and kinematics in the wind base. The H$\alpha$ lines exhibit P Cyg III type wind profiles. Deviations of the wind from spherical symmetry are shown to be small. The relatively low wind velocity (27$\div$74 km/s from different observations) and the strong intensity of the red emission (it exceeds the continuum level by up to a factor of seven) are typical for hypergiants rather than the classical supergiants. IRAS01005 +7910 is an example of spectral mimicry of a low mass post-AGB star masquerading as a massive hypergiant., Comment: 23 pages, 11 figures, 2 tables

We consider the peculiarities of the optical spectra of far evolved stars with circumstellar gaseous-dusty envelopes: the time variability of the absorption-emission profiles of the H$\alpha$ line, the presence of stationary emission and absorption molecular bands, multicomponent complex profiles of the NaI D-doublet lines. We show that the peculiarities of the line profiles (the presence of an emission component in the NaI D-doublet lines, the specific type of the molecular features, the asymmetry or splitting of the profiles of strongest absorptions with low excitation potential of the low level) can be associated with the kinematic and chemical properties of the circumstellar envelope and its morphological type., Comment: 26 pages, 2 tables, 9 figures

Observations of the yellow hypergiant Rho Cas obtained in 2007-2011 in a wide wavelength region with spectral resolution about 60000 have enabled studies of features of its optical spectrum in detail and brought to light previously unknown characteristics of the extended atmosphere of the star. The radial velocity measured from symmetric absorptions of metals varies with an amplitude of about +/-7 km/s around the systemic velocity Vsys=-47 km/s, due to low-amplitude pulsations of the atmospheric layers near the photosphere. At some times, a velocity gradient was found in deep atmospheric layers of the star. A slight velocity stratification in the stellar atmosphere was detected for the first time, manifested as a difference of 3-4 km/s in the velocities measured from absorption lines of neutral metals and of ions. The long-wavelength components of split absorptions of BaII, SrII, TiII, and other strong lines with low excitation potentials for their lower levels are distorted by nearby emission lines. It is suggested that the short-wavelength components, whose locations correspond to the narrow velocity range Vr(blue) from approximately -60 to -70 km/s, are formed in a circumstellar envelope; one component of the D~NaI doublet and the emission components of the FeII 6369.46 and 6432.68 ions are also formed there., Comment: 16 pages, 5 figures, 3 tables

High-resolution (R=60000) echelle spectroscopy of the post-AGB supergiant V5112 Sgr performed in 1996-2012 with the 6-m telescope BTA has revealed peculiarities of the star optical spectrum and has allowed the variability of the velocity field in the stellar atmosphere and envelope to be studied in detail. An asymmetry and splitting of strong absorption lines with a low lower-level excitation potential have been detected for the first time. The effect is maximal in BaII lines whose profile is split into three components. The profile shape and positions of the split lines change with time. The blue components of the split absorption lines are shown to be formed in a structured circumstellar envelope, suggesting an efficient dredge-up of the heavy metals produced during the preceding evolution of this star into the envelope. The envelope expansion velocities have been estimated to be 20 and 30 km/s. The mean radial velocity from diffuse bands in the spectrum of V5112 Sgr coincides with that from the short-wavelength shell component of the NaI D lines, which leads to the conclusion about their formation in the circumstellar envelope. Analysis of the set of radial velocities Vr based on symmetric absorption lines has confirmed the presence of pulsations in the stellar atmosphere with an amplitude 8 km/s., Comment: 16 pages, 5 figures, 3 tables

We present the results of modeling of the spectrum of the brightest stars belonging to the Cyg OB2 association - #7 (O3If*) and #11 (O5Ifc). #7 is one of the hottest stars in our Galaxy, while #11 belongs to the spectral class Ofc, which was recently introduced and yet small in numbers (Walborn et al., 2010). We determine the physical properties and chemical composition of their atmosphere using CMFGEN code. The atmosphere of #7 reveals an excess of nitrogen X(N*)/X(Nsun) = 3.2 and the carbon and oxygen deficiency X(C*)/X(Csun) = 0.08, X(O*)/X(Osun) = 0.09, while the atmosphere of #11 is enriched with carbon X(C*)/X(Csun)=1 and silicon X(Si *)/X(Si sun)=2., Comment: proceedings of conference "Massive Stars: From {\alpha} to {\Omega}", held 10-14 June 2013 in Rhodes, Greece; Online at http://a2omega-conference.net, id.84

Aiming to explore weak spectral features of stellar and interstellar origin we used the NES echelle spectrograph of the 6-m telescope to obtain high-resolution spectra for 13 hot O3 - B4 stars in the Cyg OB2 association, including a high luminous star No. 12. Velocity fields in the atmospheres and interstellar medium, characteristics of optical spectra and line profiles are investigated. The cascade star formation scheme for the association is confirmed. Evidence is presented suggesting that the hypergiant Cyg OB2 No.12 is an LBV object and that its anomalous reddening has a circumstellar nature., Comment: 35 pages, 16 figures, 6 tables

Repeated observations with high spectral resolution acquired in 1998-2008 are used to study the temporal behavior of the spectral line profiles and velocity field in the atmosphere and circumstellar envelope of the post-AGB star V448Lac. Asymmetry of the profiles of the strongest absorption lines with low-level excitation potentials less 1eV and time variations of these profiles have been detected, most prominently the profiles of the resonance lines of BaII, YII, LaII, SiII. The peculiarity of these profiles can be explained using a superposition of stellar absorption line and shell emission lines. Emission in the (0;1) 5635A Swan band of the C2 molecule has been detected in the spectrum of V448Lac for the first time. The core of the Halpha line displays radial velocity variations with an amplitude ~8 km/s. Radial velocity variations displayed by weakest metallic lines with lower amplitudes, 1-2 km/s, may be due to atmospheric pulsations. Differential line shifts, 0 -- 8 km/s, have been detected on various dates. The position of the molecular spectrum is stationary in time, indicating a constant expansion velocity of the circumstellar shell, Vexp=15.2 km/s, as derived from the C2 and NaI lines., Comment: 19 pages, 8 figures, 1 table

Splitting of the strongest absorption lines with a lower-level excitation potential $\chi<$1eV has been detected for the first time in the optical spectra of the post-AGB star V354Lac obtained with a spectral resolution R=60000 at the 6-m telescope BTA. Analysis of the kinematics shows that the short-wavelength component of the split line originates in the star's thick gas-dust envelope. Disregarding the splitting of strong lines when the chemical composition is calculated leads to overestimated excess of s-process elements (Ba, La, Ce, Nd) in the stellar atmosphere. The profiles of strong absorption lines have been found to be variable. The available radial-velocity data suggest the absence of any trend in the velocity field in the atmosphere and circumstellar envelope of V354Lac over 15 years of its observations., Comment: 12 pages, 5 figures, 1 table

FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photometric observations of the optical counterpart of IRAS 00470+6429 obtained in 2003--2008. The optical spectrum is dominated by emission lines, most of which have P Cyg type profiles. We detected significant brightness variations, which may include a regular component, and variable spectral line profiles in both shape and position. The presence of a weak Li {\sc I} 6708 \AA line in the spectrum suggests that the object is most likely a binary system with a B2--B3 spectral type primary companion of a luminosity $\log$ L/L$\odot$ = 3.9$\pm$0.3 and a late-type secondary companion. We estimate a distance toward the object to be 2.0$\pm$0.3 kpc from the Sun., Comment: 37 pages, 13 figures

The strongest absorption features with the lower-level excitation potentials $\chi_{\rm low}<1$ eV are found to be split in the high-resolution optical spectra of the post-AGB star V354 Lac taken in 2007--2008. Main parameters, T$_{eff}$=5650 K, $\log g$=0.2, $\xi_t$=5.0 km/s, and the abundances of 22 chemical elements in the star's atmosphere are found. The overabundance of the $s$-process chemical elements (Ba, La, Ce, Nd) in the star's atmosphere is partly due to the splitting of strong lines of the ions of these metals. The peculiarities of the spectrum in the wavelength interval containing the LiI $\lambda$ 6707 \AA{} line can be naturally explained only by taking the overabundances of the CeII and SmII heavy-metal ions into account. The best agreement with the synthetic spectrum is achieved assuming $\epsilon$(LiI)=2.0, $\epsilon$(CeII)=3.2, and $\epsilon$(SmII)=2.7. The velocity field both in the atmosphere and in the circumstellar envelope of V354 Lac remained stationary throughout the last 15 years of our observations., Comment: 16 pages, 6 figures, 2 tables

We present the results of high-resolution optical spectroscopy, low-resolution near-IR spectroscopy and near-infrared speckle interferometry of the massive young stellar object candidate V645 Cyg, acquired to refine its fundamental parameters and the properties of its circumstellar envelope. Speckle interferometry in the $H$- and $K$-bands and an optical spectrum in the range 5200--6680 \AA with a spectral resolving power of $R$ = 60 000 were obtained at the 6-m telescope of the Russian Academy of Sciences. Another optical spectrum in the range 4300--10500 \AA with $R$ = 79 000 was obtained at the 3.6-m CFHT. Low-resolution spectra in the ranges 0.46--1.4 $\mu$m and 1.4--2.5 $\mu$m with $R \sim$ 800 and $\sim$ 700, respectively, were obtained at the 3-m Shane telescope of the Lick Observatory. Using a novel kinematical method based on the non-linear modeling of the neutral hydrogen density profile in the direction toward the object, we propose a distance of $D = 4.2\pm$0.2 kpc. We also suggest a revised estimate of the star's effective temperature, T$_{\rm eff} \sim$25 000 K. We resolved the object in both $H$- and $K$-bands. We conclude that V645 Cyg is a young, massive, main-sequence star, which recently emerged from its cocoon and has already experienced its protostellar accretion stage. The presence of accretion is not necessary to account for the high observed luminosity of (2--6)$\times 10^4$ M$_{\odot}$ yr$^{-1}$. The receding part of a strong, mostly uniform outflow with a terminal velocity of $\sim$800 km s$^{-1}$ is only blocked from view far from the star, where forbidden lines form., Comment: 14 pages, 10 figures

BD-6^o1178 identified with the infrared source IRAS05238-0626 is shown for the first time to be a spectroscopic binary (SB2) by analyzing the high-resolution spectra taken with the NES echelle spectrograph of the 6-m telescope. The components of the binary have close spectral types and luminosity classes: F5IV-III and F3V. The heliocentric radial velocities are measured for both components at four observing moments in 2004-2005. Both stars have close rotation velocities, which are equal to 24 and 19km/s. We do not confirm the classification of BD-6^o1178 as a supergiant in the transition stage of becoming a planetary nebula. BD-6^o1178 probably is a young pre-MS stars. It is possibly a member of the 1c subgroup of the OriOB1 association., Comment: 13 pages, 1 table, 4 figures

For the first time high-resolution optical spectroscopy of the variable star V2324Cyg associated with the IR-source IRAS20572+4919 is made. More than 200 absorption features (mostly FeII, TiII, CrII, YII, BaII, and YII) are identified within the wavelength interval 4549-7880AA. The spectral type and rotation velocity of the star are found to be F0III and Vsini=69km/s, respectively. HI and NaID lines have complex PCyg-type profiles with an emission component. Neither systematic trend of radial velocity Vr with line depth Ro nor temporal variability of Vr have been found. We determined the average heliocentric radial velocity Vr=-16.8\pm 0.6km/s. The radial velocities inferred from the cores of the absorption components of the H$\beta$ and NaI wind lines vary from -140 to -225km/s (and the expansion velocities of the corresponding layers, from about 120 to 210km/s). The maximum expansion velocity is found for the blue component of the split H$\alpha$ absorption: 450km/s for December 12, 1995. The model atmospheres method is used to determine the star's parameters: Teff=7500K, log g=2.0, $\xi_t$=6.0km/s, and metallicity, which is equal to the solar value. The main peculiarity of the chemical abundances pattern is the overabundance of lithium and sodium. The results cast some doubt on the classification of V2324Cyg as a post-AGB star., Comment: 28 pages, 6 figures

Repeated spectroscopic observations made with the 6m telescope of yielded new data on the radial-velocity variability of the anomalous yellow supergiant QYSge. 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 (16km/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 10km/s are revealed. The absorption lines in the spectrum of QYSge have a substantial width of FWHM~45 km/s. The method of model atmospheres is used to determine the following parameters: Teff=6250K, lg g=2.0, and microturbulence Vt=4.5km/s. The metallicity of the star is found to be somewhat higher than the solar one 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 alpha-process elements Mg, Si, and Ca are slightly overabundant [alpha/H]=+0.12. The strong sodium excess, [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 QYSge do not give grounds for including this star into the group of RCrB or RVTau-type type objects., Comment: 29 pages, 8 figures, 4 tables; accepted by Astrophys. Bulletin

Based on high-resolution observations (R=60000 and 75000), we have studied the optical spectral variability of the star BD+48 1220 (IRAS05040+4820). We have measured the equivalent widths of numerous absorption lines of neutral atoms and ions at wavelengths from 4500 to 6760 AA, as well as the corresponding radial velocities. We use model atmospheres to determine Teff=7900K, log g=0.0, microturbulence velocity xi_t=6.0, and the abundances for 16 elements. The star's metallicity differs little from the solar value: [Fe/H]=-0.10 dex. The main peculiarity of the chemical composition of the star is a large He-excess, derived from the HeI 5876 A absorption, [He/H]=+1.04, and the equally large O-excess, [O/Fe]=+0.72 dex. The C-excess is small, [C/Fe]=+0.09 dex, and the ratio [C/O]$\le$ 1. We obtained a revised relation for the light-metal abundances: [Na/Fe]=+0.87 with [Mg/Fe]=-0.31. The barium abundance is low, [Ba/Fe]=-0.84. The radial velocity of the star measured from photospheric absorption lines over three years of observations varies in the interval V_sun = -(7 - 15) km/s. Time variable differential line shifts have been revealed. The entire set of available data (the luminosity Mv~-5m, velocity V_lsr~-20 km/s, metallicity [Fe/H]=-0.10, and peculiarities of the optical spectrum and chemical composition) confirms the status of BD+48 1220 as a post-AGB star with He- and O-excesses belonging to the Galactic disk., Comment: 42 pages, 7 figures, 6 tables, accepted by Astronomy Reports

We studied in detail the optical spectrum of the post-AGB star HD56126 (IRAS07134+1005). We use high resolution spectra (R=25000 and 60000) obtained with the echelle spectrographs of the 6-m telescope. About one and a half thousand absorptions of neutral atoms and ions, absorption bands of C_2, CN, and CH molecules, and interstellar bands (DIBs) are identified in the 4010 to 8790 AA wavelength region, and the depths and radial velocities of these spectral features are measured. Differences are revealed between the variations of the radial velocities measured from spectral features of different excitation. In addition to the well-known variability of the Halpha profile, we found variations in the profiles of a number of FeII, YII, and BaII lines. We also produce an atlas of the spectrum of HD56126 and its comparison staralpha Per. The full version of the atlas is available in electronic form from Web-address: http://www.sao.ru/hq/ssl/Atlas/Atlas.html, Comment: 42 pages, 6 figures

For the first time, we obtained the high-resolution (R=15000 and 60000) optical spectra for the extremely luminous star No.12, associated with the IR-source IRAS20308+4104, a member of the CygOB2 association. We have found about 200 spectral features in range 4552-7939AA, including the interstellar NaI, KI lines and numerous DIBs, which are the strongest absorption lines in the spectrum, along with the HeI, CII, and SiII lines. A two-dimensional spectral classification indicates that the spectral type is B5+/-0.5 Ia+. Our analysis of the Vr data shows the presence of a Vr gradient in the stellar atmosphere, caused by the infall of matter onto the star. The strong Halpha emission displays broad Thompson wings and time-variable core absorption, providing evidence that the stellar wind is inhomogeneous, and a slightly blue-shifted PCyg type absorption profile. We concluded that the wind is variable in time., Comment: 20 pages, 5 figures, 2 tables

Over the five years of high-resolution spectroscopy of the cool star identified with the IR source IRAS20508+2011, the photospheric radial velocity variability Vr=15-30km/s is detected. In the same time, the Halpha profile varied from an intense bell-shaped emission line with a small absorption to 2-peaked emission with a central absorption feature below the continuum level. The NaD doublet lines shown a complex profile with broad (FWHM \approx 120km/s) emission and photospheric absorption, as well as an interstellar component. We used model atmospheres to determine the physical parameters and chemical composition of the star's atmosphere: Te=4800K, log g=1.5, [Fe/H]=-0.36, [O/Fe] =+1.79 (with the ratio [C/O]=-0.9). The totality of the parameters suggests that the optical component of IRAS20508+2011 is an O-rich AGB star with luminosity Mv, Comment: 26 pages, 4 PS-figures, 4 tables, uses A&A style