NASA NTRS1995
One-dimensional hydrostatic models of quiet and active solar regions can be constructed that generally account for the observed intensities of lines and continue throughout the spectrum, except for the infrared CO lines. There is an apparent conflict between: (1) observations of the strongest infrared CO lines formed in LTE at low-chromospheric heights but at temperatures much cooler than the average chromospheric values; and (2) observations of Ca II, UV (ultraviolet), and microwave intensities that originate from the same chromospheric heights but at the much higher temperatures characteristic of the average chromosphere. A model M(sub CO) has been constructed which gives a good fit to the full range of mean CO line profiles (averaged over the central area of the solar disk and over time) but this model conflicts with other observations of average quiet regions. A model L(sub CO) which is approximately 100 K cooler than M(sub CO) combined with a very bright network model F in the proportions 0.6 L(sub CO) + 0.4 F is found to be generally consistent with the CO, Ca II, UV, and microwave observations. Ayres, Testerman, and Brault found that models COOLC and FLUXT in the proportions 0.925 and 0.075 account for the CO and Ca II lines, but these combined models give an average UV intensity at 140 nm about 20 times larger than observed. The 0.6 L(sub CO) + 0.4 F result may give a better description of the cool and hot components that produce the space- and time-averaged spectra. Recent observations carried out by Uitenbroek, Noyes, and Rabine with high spatial and temporal resolution indicate that the faintest intensities in the strong CO lines measured at given locations usually become much brighter within 1 to 3 minutes. The cool regions thus seem to be mostly the low-temperature portions of oscillatory waves rather than cool structures that are stationary.