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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

As part of the Araucaria Project, we present the first spectral catalog ofsupergiant stars in the Local Group dwarf irregular galaxy WLM. In assigning aspectral classification to these stars we accounted for the low metal contentof WLM relative to the galactic standards used in the MK process, by usingclassification criteria developed for B and A supergiants contained in theSmall Magellanic Cloud. Our spectral catalog shows that our higher S/Nspectroscopic sample of 19 objects contains at least 6 early-B (B0-B5)supergiants and 6 late-B and early-A (B8-A2) stars of luminosity class betweenIa and II, as well as an O7~V star and an O9.7 Ia star. The spectra of severalof these stars is of sufficiently high quality for a determination of thestellar parameters and abundances. We have acquired also a second set of lowerS/N spectra for mostly BA stars, however their quality does not allow a furtheranalysis. We have carried out a quantitative analysis for three early-Bsupergiants. The mean oxygen abundance we derive is 12+log(O/H)=7.83 +/- 0.12.This value agrees very well with the measurement that is obtained from HIIregions. We therefore find no additional evidence for the discrepancy betweenstellar and nebular oxygen abundances measured for a single A-type supergiantby Venn et al. The analysis of B- and A-type supergiants yields compatibleresults for nitrogen, silicon and magnesium. We show that the photometricvariability of the blue supergiants included in our spectroscopic sample isnegligible for the use of these stars as distance indicators.Comment: Accepted for publication in the Astrophysical Journal. 14 pages, 10  figure

The Araucaria Project: VLT Spectra of Blue Supergiants in WLM— Classification and First Abundances