Stellar distances from spectroscopic observations: a new technique
  A Bayesian approach to the determination of stellar distances from
photometric and spectroscopic data is presented and tested both on pseudodata,
designed to mimic data for stars observed by the RAVE survey, and on the real
stars from the Geneva-Copenhagen survey. It is argued that this method is
optimal in the sense that it brings to bear all available information and that
its results are limited only by observational errors and the underlying physics
of stars. The method simultaneously returns the metallicities, ages and masses
of programme stars. Remarkably, the uncertainty in the output metallicity is
typically 44 per cent smaller than the uncertainty in the input metallicity.
