摘要：Bromine (Z= 35) and antimony (Z= 51) are extremely difficult to detect in stars. In very few instances, weak and mostly uncertain identifications of BrI, BrII, and SbIIin relatively cool, chemically peculiar stars were successful. Adopted solar abundance values rely on meteoritic determinations. Here, we announce the first identification of these species in far-ultraviolet spectra of hot stars (with effective temperatures of 49 500–70 000 K), namely in helium-rich (spectral type DO) white dwarfs. We identify the BrVIresonance line at 945.96 Å. A previous claim of Br detection based on this line is incorrect because its wavelength position is inaccurate by about 7 Å in atomic databases. Taking advantage of precise laboratory measurements, we identify this line as well as two other, subordinate BrVIlines. Antimony is detected by the SbVresonance doublet at 1104.23/1225.98 Å as well as two subordinate SbVIlines. A model-atmosphere analysis reveals strongly oversolar Br and Sb abundances that are caused by radiative-levitation dominated atomic diffusion.
关键词：Key wordsendiffusionstars: abundancesstars: atmospheresstars: AGB and post-AGBwhite dwarfs
