Radial velocity measurements with stellar spectrographs of the 6-m telescope

Клочкова, В. Г.; Панчук, В. Е.; Yushkin, M. V.; Nasonov, Dmitry

doi:10.1134/s199034130804007x

Cited by 23 publications

(16 citation statements)

References 9 publications

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“…Procedures for obtaining radial velocities from the SAO spectra are described by Klochkova et al (2008). The list of selected lines is taken from the line list for the post-AGB F supergiant HD 56126 ) and again the stability of the spectrograph was checked using telluric ([O i], H2O and O2) lines.…”

Section: Radial Velocitiesmentioning

confidence: 99%

HD 179821 (V1427 Aql, IRAS 19114+0002) – a massive post-red supergiant star?

Şahìn

Lambert

Клочкова

et al. 2016

Mon. Not. R. Astron. Soc.

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We have derived elemental abundances of a remarkable star, HD 179821, with unusual composition (e.g. [Na/Fe]=1.0±0.2 dex) and extra-ordinary spectral characteristics. Its metallicity at [Fe/H]=0.4 dex places it among the most metal-rich stars yet analyzed. The abundance analysis of this luminous star is based on high resolution and high quality (S/N≈120-420) optical echelle spectra from McDonald Observatory and Special Astronomy Observatory. The data includes five years of observations over twenty-one epochs. Standard 1D LTE analysis provides a fresh determination of the atmospheric parameters over all epochs: T eff = 7350±200 K, log g= +0.6±0.3, and a microturbulent velocity ξ = 6.6±1. Eu is overabundant relative to the anticipated [X/Fe] ≈ 0.0. Some peculiarities of its optical spectrum (e.g. variability in the spectral line shapes) is noticed. This includes the line profile variations for Hα line. Based on its estimated luminosity, effective temperature and surface gravity, HD 179821 is a massive star evolving to become a red supergiant and finally a Type II supernova.

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Section: Radial Velocitiesmentioning

confidence: 99%

HD 179821 (V1427 Aql, IRAS 19114+0002) – a massive post-red supergiant star?

Şahìn

Lambert

Клочкова

et al. 2016

Mon. Not. R. Astron. Soc.

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“…The accuracy is somewhat poorer in the case of ρ Cas, since the spectral lines are broadened by turbulence: the microturbulence velocity in the atmosphere reaches 11 km/s [1]. The techniques used for the Vr measurements derived from spectra taken with the NES spectrograph, their uncertainties, and the sources of these uncertainties are described in more detail in [16,17].…”

Section: Observations Reduction and Spectral Analysismentioning

confidence: 99%

Instability of the kinematic state in the atmosphere of the hypergiant ρ Cas outside outburst

Клочкова

Панчук²,

Tavolzhanskaya³

et al. 2014

Astron. Rep.

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Observations of the yellow hypergiant ρ Cas obtained in 2007-2011 in a wide wavelength region with spectral resolution R ≥60 000 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 6432.68Å ions are also formed there.

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“…The last column of Table 1 indicates whether a correction has been applied, and the residual errors for each spectrum. For a more detailed description of the procedure of radial velocity Vr measurement from the spectra taken with the NES spectrograph, and the sources of errors, see [22]. The r.m.s.…”

Section: Observations and Reduction Of Spectramentioning

confidence: 99%

Spectral variability of the peculiar A-type supergiant 3Pup

2010

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Optical spectra of the peculiar supergiant 3 Pup taken in 1997-2008 are used to study the spectral peculiarities and velocity field in its atmosphere. The profiles of strong FeII lines and of the lines of other ions have a specific shape: the wings are raised by emissions, whereas the core is sharpened by a depression. The latter feature becomes more pronounced with the increasing line strength, and the increasing wavelength. Line profiles are variable: the magnitude and sign of the absorption asymmetry, and the blue-to-red emission intensity ratios vary from one spectrum to another. The temporal Vr variations are minimal for the forbidden emissions and sharp shell cores of the absorption features of FeII(42), and other strong lines of iron-group ions. Therefore the average velocity for the above lines can be adopted as the systemic velocity: V sys = 28.5 ± 0.5 km/s. The weakest photospheric absorptions and photospheric MgII, SiII absorptions exhibit well-defined day-to-day velocity variations of up to 7 km/s. Quantitative spectral classification yields the spectral type of A2.7 ± 0.3 Ib. The equivalent widths and profiles of Hδ and Hγ, and the equivalent width of the OI 7774Å triplet yield an absolute magnitude estimate of M v = −5. m 5 ± 0. m 3, implying the heliocentric distance of 0.7 kpc.

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Radial velocity measurements with stellar spectrographs of the 6-m telescope

Cited by 23 publications

References 9 publications

HD 179821 (V1427 Aql, IRAS 19114+0002) – a massive post-red supergiant star?

HD 179821 (V1427 Aql, IRAS 19114+0002) – a massive post-red supergiant star?

Instability of the kinematic state in the atmosphere of the hypergiant ρ Cas outside outburst

Spectral variability of the peculiar A-type supergiant 3Pup

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