The classification of helium-rich hot subdwarfs
C.S.Jeffery, J.S.Drilling, P.M.Harrison, U.Heber, S.Moehler
We introduce a spectral
classification system for helium-rich hot subdwarfs based on
1.5 Angstrom spectra of high S/N. Based on a small number of
absorption line ratios, the scheme is logically constructed and
can be extended to similar spectra of all hot subdwarfs.