Amplitude Modulation of Cepheid Radial Velocity Curves as a Systematic   Source of Uncertainty for Baade-Wesselink Distances
  I report on the recent discovery of modulation in the radial velocity curves in four classical Cepheids. This discovery may enable significant improvements in the accuracy of Baade-Wesselink distances by revealing a not previously considered systematic source of uncertainty. 
Richard I. Anderson
astro-ph.SR