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

(Abridged) We provide empirical constraints on the different physicalcomponents that can act to yield temporal variability in predominantly orpartially wind-formed optical lines of luminous OB stars, and thus potentiallyaffect the reliable determination of fundamental parameters, includingmass-loss rates via clumped winds. Using time-series spectroscopy from epochsspread over $\sim$ 4 years, a case study of the O9.5 supergiant $\alpha$ Cam ispresented. We demonstrate that the He I 5876 (2$^3$P$^0$--3$^3$D) line is animportant diagnostic for photospheric and wind variability in this star. Theoptical line profiles of $\alpha$ Cam are affected by (i) deep-seatedfluctuations close to, or at, the photosphere, (ii) atmospheric velocitygradients, and (iii) large-scale stellar wind structure. This study providesnew empirical perspectives on accurate line-synthesis modelling of stellar windsignatures in massive luminous stars. Using a pure Halpha line-synthesis codewe interpret maximum changes in the red-ward and peak emission of $\alpha$ Camin terms of mass-loss rate differences in the range $\sim$ 5.1 $\times$10$^{-6}$ to 6.5 $\times$ 10$^{-6}$ M$_\odot$ yr$^{-1}$. However, the modelsgenerally fail to reproduce the morphology of blueward (possibly absorptive)regions of the profiles.Comment: Accepted for pulication in A&A; 9 pages and 8 figure

The superimposed photospheric and stellar wind variability of the O-type supergiant $\mathsf{\alpha}$ Camelopardalis