STELLAR CORONAL ABUNDANCES .3. THE SOLAR FIRST IONIZATION-POTENTIAL EFFECT DETERMINED FROM FULL-DISK OBSERVATION

In this paper we reanalyze the full-disk quiet-sun spectrum of Malinovsky and Heroux (1973) with modern atomic data. The purposes of this are to check our atomic data and methods in other investigations using data from nearby stars obtained with the NASA Extreme Ultraviolet Explorer satellite, and to confirm that the solar FIP effect investigated by previous authors studying discrete solar regions is the same as that found in full-disk spectra. We recover the usual solar FIP effect of a coronal abundance enhancement of elements with a low first ionization potential (FIP) of a factor similar to 3-4 for lines formed at temperatures greater than similar to 10(6) K. For lower temperatures, the FIP effect seems to be substantially smaller, in qualitative agreement with other data. Comparing our fill-disk result with those from discrete solar structures suggest that the FIP effect is a function of altitude, with the lower temperature full-disk emission being dominated by the super-granulation network. We also compare the recent Fe ionization balance of Arnaud and Raymond (1992) with that of Arnaud and Rothenflug (1985).