2007ApJ...668L..59V

Based on photometric and astrometric data it has been proposed that Albus 1 (also known as CPD -20 1123) might be a hot white dwarf similar to G191-B2B or, alternatively, a hot subdwarf. We obtained a series of optical spectra showing that CPD -20 1123 is a bright He-B subdwarf. We analyzed the H I Balmer and He I line spectra and measured T_eff= 19,800 ± 400 K, logg=4.55±0.10, and logN(He)/N(H)=0.15±0.15. This peculiar object belongs to a family of evolved helium-rich stars that may be the products of double-degenerate mergers, or, alternatively, the products of post horizontal- or giant-branch evolution.