English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Repeated observations with high spectral resolution acquired in 1998-2008 areused to study the temporal behavior of the spectral line profiles and velocityfield in the atmosphere and circumstellar envelope of the post-AGB starV448Lac. Asymmetry of the profiles of the strongest absorption lines withlow-level excitation potentials less 1eV and time variations of these profileshave been detected, most prominently the profiles of the resonance lines ofBaII, YII, LaII, SiII. The peculiarity of these profiles can be explained usinga superposition of stellar absorption line and shell emission lines. Emissionin the (0;1) 5635A Swan band of the C2 molecule has been detected in thespectrum of V448Lac for the first time. The core of the Halpha line displaysradial velocity variations with an amplitude ~8 km/s. Radial velocityvariations 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 isstationary in time, indicating a constant expansion velocity of thecircumstellar shell, Vexp=15.2 km/s, as derived from the C2 and NaI lines.

Peculiarities and variations in the optical spectrum of the post-AGB star V448Lac=IRAS22223+4327