Free Access

Fig. 3


A set of FEROS spectra illustrating the combined effect of rotation and high spectral resolution on the central depth of the strategic He I λ4026, 4471 and He II λ4200, 4541 lines, for stars of similar spectral type (as attributed by Walborn) and similar log W′, as measured from our high-resolution data. Note that in the Walborn scheme the O7 subtype is defined by He I λ4471   ≈  He II λ4541 , whereas in our spectra He I λ4471   is always deeper than He II λ4541  (although its EW is actually smaller, log W′ ≤  0), indicating a spectral type of O8–8.5.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.