New in the optical spectrum and kinematic state of the atmosphere of the variable V1027 Cyg (=IRAS 20004+2955)

Клочкова, В. Г.; Панчук, В. Е.; Tavolzhanskaya, N. S.

doi:10.1134/s1063773716120033

Cited by 3 publications

(5 citation statements)

References 32 publications

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“…A more detailed study of the characteristics of the spectrum and the velocity field in the atmosphere of V1027 Cyg was carried out based on the high spectral resolution observations with the NES echelle spectrograph of the 6-m telescope [61]. From the symmetric absorptions of a low and moderate intensity, slight variations in radial velocity V r (abs) were revealed with an amplitude of about 5 km s −1 occurring due to pulsations.…”

Section: Cool Agb Supergiantsmentioning

confidence: 99%

Spectroscopy of Supergiants with Infrared Excess: Results of 1998–2018

Клочкова

2019

Astrophys. Bull.

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The results of our second stage of the detailed spectroscopy of peculiar supergiants identified with galactic infrared sources, performed 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 Li excess was found in the atmospheres of peculiar supergiants V2324 Cyg and V4334 Sgr. The results of investigation of the kinematical parameters 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.

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Section: Cool Agb Supergiantsmentioning

confidence: 99%

Spectroscopy of Supergiants with Infrared Excess: Results of 1998–2018

Клочкова

2019

Astrophys. Bull.

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“…We have discovered the peculiarities, previously unknown in the optical spectra of the AGBcandidate stars. In particular, based on the observations, also performed with the NES echelle spectrograph of the 6-m telescope, the spectral features and the velocity fields in the atmosphere and the envelope of the cool AGB-supergiant V1027 Cyg [11], the optical component of the IR source IRAS 20004+2955 were studied. For the first time, the spectrum of this star revealed the splitting of the cores of strong metal absorptions and their ions (Si II, Ni I, Ti I, Ti II, Sc II, Cr I, Fe I, Fe II, Ba II).…”

Section: Introductionmentioning

confidence: 99%

On the Evolutionary State of High-Latitude Variable V534 Lyr

2018

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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 V r 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 dates. The analysis of the velocity field examining the lines of various nature revealed a low-amplitude variability of V r 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 V sys ≈ −125 km s −1 (V lsr ≈ −105 km s −1 ). The distance estimate of d ≈ 6 kpc for the star leads us to its absolute magnitude of M V ≈ −5. m 3, 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 ∆V r = 20-50 km s −1 . A combination of the parameters: reduced metallicity [Met/H] ⊙ = −0.28, increased nitrogen abundance [N/Fe] = +1.10, large spatial velocity, high luminosity, a strong variability of the emission-absorption profiles of H I lines, splitting of metal absorptions at different times of observations and the variability of the velocity field in the atmosphere allow us to classify V534 Lyr as a pulsating star near the HB and belonging to the thick disk of our Galaxy.

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“…Currently, with the very limited observational data available for this object, we cannot identify firm explanations for its spectral features, but we can make some guesses. Judging from the IR uxes measured in [1], RAFGL 5081 is located in region IV on the [12][13][14][15][16][17][18][19][20][21][22][23][24][25]- IR-color diagram presented in [22], which contains stars with high mass-loss rates and optically thick circumstellar envelopes. In addition, the spectral energy distribution of RAFGL 5081 [1] indicates that the envelope has not yet separated from the central star.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

“…Later, based on the results of monitoring V1027 Cyg with the NES spectrometer on the 6-m telescope, a feature that was previously unknown for stars close to the AGB was detected in its spectrum [21]. Klochkova et al [21] discovered splitting of the cores of strong absorption lines of metals and their ions (Si II, Ni I, Ti I, Ti II, Sc II, Cr I, Fe I, Fe II, Ba II). It turned out that the broad profiles of strong lines contain a stable weak emission feature in the line cores, which splits the profile into components.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

“…That source also lacks radio spectroscopy, however, SAO 6-m spectra were used to determine the fundamental parameters of the atmosphere of the central star and the abundances of a large number of elements [20]. Later, based on the results of monitoring V1027 Cyg with the NES spectrometer on the 6-m telescope, a feature that was previously unknown for stars close to the AGB was detected in its spectrum [21]. Klochkova et al [21] discovered splitting of the cores of strong absorption lines of metals and their ions (Si II, Ni I, Ti I, Ti II, Sc II, Cr I, Fe I, Fe II, Ba II).…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

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Non-stationary wind in the system of the infrared source RAFGL 5081

Клочкова¹,

Ченцов²,

Панчук³

et al. 2017

Astron. Rep.

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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 Na I D lines, and the Hα 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 Na I D and Hα 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 Na I D and Hα 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 Na I (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.

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New in the optical spectrum and kinematic state of the atmosphere of the variable V1027 Cyg (=IRAS 20004+2955)

Cited by 3 publications

References 32 publications

Spectroscopy of Supergiants with Infrared Excess: Results of 1998–2018

Spectroscopy of Supergiants with Infrared Excess: Results of 1998–2018

On the Evolutionary State of High-Latitude Variable V534 Lyr

Non-stationary wind in the system of the infrared source RAFGL 5081

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