The development of opacity databases for brown dwarfs and extra solar giant planets

The accurate modeling of the atmospheric opacity of brown dwarfs and extra solar giant planets (ESP) requires atomic and molecular opacities that cover a wide range of physical parameters, and frequently involves species that, for a variety of reasons, have not been well studied, either in the laboratory or theoretically. Even when good laboratory data is available, information on lines that originate from excited levels, only populated at high temperatures, is frequently missing from the tabulation. This results in missing opacity from the 'hot' bands of molecules. Other problems with laboratory data include the inability to analyze bands that are not resolved on a line by line basis (many of the bands of CH4 fall into this category), or the difficulty in conducting laboratory experiments and measurements on highly reactive species. This implies that molecular opacity generated using only data derived from laboratory studies may be incomplete and will underestimate the true opacity, especially at higher temperatures.