BPS CS22892-0052 is an old population II star located at a distance of 4.7 kiloparsecs in the Milky Way's galactic halo. It belongs to a class of ultra-metal-poor stars, specifically the very rare subclass of neutron-capture (r-process) enhanced stars. It was discovered by Tim C. Beers and collaborators with the Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory in Chile. Extended high-resolution spectroscopic observations since around 1995 allowed observers to determine the abundances of 53 chemical elements in this star, as of December 2005 only second in number to the Sun.