A few things we do not know about the sun and F stars and G stars
  WE do not know how to make realistic model atmospheres; understand convection; consider the variation in microturbulent velocity; understand spectroscopy; have good spectra of the sun or any other star; have energy distributions for the sun or any other star; know how to determine abundances; know the abundances of the sun or any other star; have good atomic and molecular data; One half the lines in the solar spectrum are not identified. We should get our own house in order before worrying about the neighbors. 
Robert L. Kurucz (Smithsonian Astrophysical Observatory)