The Sun in Si I, C IV, O IV, N V, O V, Ne VIII

The Sun in Si I, C IV, O IV, N V, O V, Ne VIII
observed by SUMER 07.-16.Jun.96

At four times in June 1996, SUMER rastered the Sun in two sets of three lines, nameley:

line   wave-    temp. 07.Jun 07.Jun 14.Jun 16.Jun
       lgth.(Å) (K)   15:49  23:40  11:46  11:31
--------------------------------------------------
Si I    1256    6000           X      X
C IV    1548  100000    X                    X
O IV     787  140000    X                    X
N V     1238  170000           X      X
O V      629  220000           X      X
Ne VIII  770  600000    X                    X

The raster step size was 3.01 arcsec, the exposure time 2 seconds per raster step. The slit image was binned in north-south direction such that approx. 3 arcsec became 1 pixel. The spectral information was compressed to one intensity value by integrating a spectral window of approx. 2.2 Å in first order (around Si I, C IV, N V), or 1.1 Å in second order (around O IV, O V, Ne VIII).

Thus losing some of SUMER's resolutional power, it was possible to collect three full disk images simultaneously in less than 4 hours. Each of these images was put together from 4630 rasters. Missing data were substituted by averaging their neighbours. Some image processing was applied.

The pictures above - which were all taken on 07.Jun.96, though at different times - show a prominence at the south-east limb in the six wavelengths discussed here.

The study was initiated by Don Hassler (HAO/NCAR).