Nebular and Auroral Emission Lines of [Ar IV] in the Optical Spectra of Planetary Nebulae

摘要

These results provide observational support for the accuracy of the theoretical ratios and, hence, the atomic data adopted in their derivation. In addition, they imply that the 7171 A deg line is not as seriously affected by telluric absorption as previously thought. However, the observed values of R_2 are mostly larger than the theoretical high-temperature and density limit, which is due to blending of the Ar IV 7237.54 A deg line with the strong C II transition at 7236 A deg.