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

In spite of large overabundances of Xe II observed in numerousmercury-manganese (HgMn) stars, Xe II oscillator strengths are only availablefor a very limited number of transitions. As a consequence, severalunidentified lines in the spectra of HgMn stars could be due to Xe II. Inaddition, some predicted Xe II lines are redshifted by about 0.1 A from stellarunidentified lines, raising the question about the wavelength accuracy of theXe II line data available in the literature. For these reasons we investigatedthe Xe II lines lying in the 3900-4521 A, 4769-7542 A, and 7660-8000 A spectralranges of four well-studied HgMn stars. We compared the Xe II wavelengthslisted in the NIST database with the position of the lines observed in thehigh-resolution UVES spectrum of the xenon-overabundant, slowly rotating HgMnstars HR 6000, and we modified them when needed. We derived astrophysicaloscillator strengths for all the Xe II observed lines and compared them withthe literature values, when available. In this framework, we performed acomplete abundance analysis of HD 71066, while we relied on our previous worksfor the other stars. We find that all the lines with wavelengths related to the6d and 7s energy levels have a corresponding unidentified spectral line,blueshifted by the same quantity of about 0.1 A in all the four stars, so thatwe identified these lines as coming from Xe II and modified their NISTwavelength value according to the observed stellar value. We find that the XeII stellar oscillator strengths may differ from one star to another from 0.0dex to 0.3 dex. We adopted the average of the oscillator strengths derived fromthe four stars as final astrophysical oscillator strength.

Wavelengths and oscillator strengths of Xe II from the UVES spectra of four HgMn stars