The availability of reliable atomic and molecular opacity tables is essential in a wide variety of astronomical models such as the solar and stellar interiors, stellar and planetary atmospheres, stellar evolution, pulsating stars and protoplanetary disks, to name a few. With the advent of powerful observational techniques, e.g. helio and asteroseismology, solar neutrino-flux measurements and exoplanet probes, of 3D hydrodynamic atmospheric simulations that include NLTE and granulation effects, of high-performance atomic and molecular computing and innovative plasma experiments, the accuracy and completeness of the opacity tables are being taken to unprecedented levels.
The Workshop on Astrophysical Opacities (WAO) intends to gather opacity data producers and consumers from both the atomic and molecular sectors in order to contribute to solving outstanding problems and to develop more effective and integrated interfaces. The last time such a workshop took place was at the IBM Venezuela Scientific Center, Caracas, Venezuela, in July 1991. Taken into consideration the success of this first WAO and the huge scientific advancements that have taken place since then in most related research fields, we have been encouraged to organize a second event. The present WAO will be held at Western Michigan University in the very welcoming town of Kalamazoo, Michigan, USA, where everything good is easily within reach. Contributed papers and student participation is specially encouraged.