Fig. 1

Spectra of He-normal stars for which hydrogen is dominant and either helium lines of both ionization states or metallic lines are visible. The lines marked are H + HeII λλ 4101, 4340, 4861; HeII λλ 4200, 4541, 4686; NV λ 4604–20; OIV λ 4632; CIV λ 4658 blend; SiIII λ 4552–68; HeI λλ 4144, 4387, 4471, 4713; SiII λ 4128–30; MgII λ 4481; and λλ 4360, 4369, 4772 emission.
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.