Detection of heavy-metal lines in the spectrum of the circumstellar envelope of a post-AGB star |
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Authors: | V. G. Klochkova |
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Affiliation: | (1) Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhys, Russia |
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Abstract: | Splitting of the strongest absorption lines with a lower-level excitation potential χ low < 1 eV has been detected for the first time in the optical spectra of the post-AGB star V354 Lac obtained with a spectral resolution R = 60 000 at the 6-m BTA telescope. 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 overabundances 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 changes in the velocity field in the atmosphere and circumstellar envelope of V354 Lac over 15 years of its observations. |
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Keywords: | stellar evolution post-AGB stars envelopes spectra |
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