The Solar FIP Effect Determined from Full Disk Observations

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Session 5 -- Chromospheres/Coronae/Active Binaries
Display presentation, Monday, 30, 1994, 9:20-6:30

[5.21] The Solar FIP Effect Determined from Full Disk Observations

J. Martin Laming (SFA Inc/Nav Res Lab), Jeremy J. Drake (CEA/UCB), Kenneth G. Widing (Nav Res Lab)

In this paper we reanalyze the full disk quiet sun spectrum of Malinovksy \& 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 (EUVE) 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, since stellar observations are necessarily full disk. We recover the usual solar FIP effect of a coronal abundance enhancement of elements with a low first ionization potential (FIP) of a factor $\sim 3-4$ for lines formed at temperatures greater than $\sim 10^6$ K. For lower temperatures the FIP effect seems to be substantially smaller, in qualitative agreement with other investigations. We also compare the recent Fe ionization balance of Arnaud \& Raymond (1992) with that of Arnaud \& Rothenflug (1985).

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