Atomic Data, Stellar Atmospheres, and the Hubble Space Telescope

Extract

Since the birth of astronomical spectroscopy in the last century astronomers have appealed for atomic and molecular data. As capabilities at astronomical observatories have grown, and now as a large orbiting telescope equipped with a high-resolution ultraviolet spectrometer is returning novel data, our appeals continue. The appeals are not rooted in exotic chemical compositions and severely extreme physical conditions to be found in stellar atmospheres. Rather the appeals arise very often because stellar atmospheres are more extensive light sources than can be attained in laboratories. The inability to replicate stellar conditions in the laboratory applies to all types of stars. The theoretical quantum chemist/physicist is not so limited as the experimental spectroscopist. Although much vital data can now be supplied through computations, experimental data is absolutely required in many areas: e.g., detailed lists of classified lines, accurate cross-sections for a variety of collisional processes needed for studies of non-LTE line formation.