SUMER Scan List

Limb brightening

To calculate the limb brightening at the solar equator, several scans were taken into consideration to represent various typical formation temperatures. To get a good signal-to-noise ration, two equatorial scans ("4" and "5") were used from full-disk scans between 28 Jan 1996 and 26 Jun 1996, and an equatorial-hole scan with a small piece of limb was used from 30 Aug 1996. Images can be seen in the various chapters of Atlas Vol. I.

The following table shows:

the date when the scan was taken
line name and wavelength in Å
log(formation temperature in K)
the value of the maximal limb brightening
the location of the maximal limb brightening (or the last pixel before the steepest descent for lines without limb brightening) in arcsec above photospheric limb
the "upper limit" of the line radiance (defined as the location where the radiance drops below 50% of the average disk value) in arcsec above photospheric limb

Each entry in the following list is linked to images showing the limb brightening vs. distance from solar center: first the whole interval, then a 50" interval around the photospheric limb. "Average disk radiance" is defined as the mean radiance within 700" from the solar center. "Limb brightening" is defined as radiance vs. distance from solar center, divided by average disk radiance. The second image also includes the value of the average disk radiance (corrected for exposure time and pixel size) in SUMER count s^-1 arcsec^-2 line^-1.

The estimate of the real SUMER step size was updated once more such that now the various lines and continua are situated 1" to 2" further above the photospheric limb.

 date       line          logT  bright  max   end   remarks
----------|-------------|------|------|-----|-----|---------
28 Jan 96 | C III   977 | 4.85 | 3.0  |  5  | 15  |         
02 Feb 96 | Ne VIII 770 | 5.80 | 9.5  | 10  |  ?  |         
04 Feb 96 | C IV   1548 | 5.01 | 17.  |  4  | 16  |         
04 Feb 96 | Cont   1549 | 4.00 | 1.3  |  1  |  6  |         
26 Feb 96 | O IV    790 | 5.24 | 2.9  |  7  | 14  |         
26 Feb 96 | Cont    804 | 4.20 | 1.1  |  6  | 11  |         
02 Mar 96 | He I    584 | 4.30 | 0.9  |  6  | 10  |         
02 Mar 96 | Cont   1169 | 4.00 | 3.8  |  1  |  7  |         
07 Apr 96 | H I Lye 937 | 4.20 | 2.1  |  3  | 11  |  [1]    
07 Apr 96 | S VI    933 | 5.31 | 15.  |  4  | 14  |         
07 Apr 96 | S VI    944 | 5.31 | 15.  |  4  |  ?  |  [2]    
07 Jun 96 | C IV   1548 | 5.01 | 8.5  |  6  | 15  |  [1]    
07 Jun 96 | O IV    787 | 5.24 | 3.1  |  6  | 17  |  [1]    
07 Jun 96 | Ne VIII 770 | 5.80 | 6.9  | 13  |  ?  |  [1]    
07 Jun 96 | Si I   1256 | 4.00 | 3.0  |  2  |  7  |  [1]    
07 Jun 96 | N V    1238 | 5.25 | 12.  |  5  | 16  |  [1]    
07 Jun 96 | O V     629 | 5.37 | 3.5  |  8  | 18  |  [3]    
26 Jun 96 | He I    584 | 4.30 | 1.1  |  5  | 13  |  [1]    
30 Aug 96 | Cont   1241 | 4.00 | 3.9  |  1  |  6  |         
30 Aug 96 | C I    1249 | 4.00 | 3.1  |  1  |  5  |         
30 Aug 96 | Si II  1250 | 4.14 | 6.1  |  3  |  9  |         
30 Aug 96 | S II   1250 | 4.10 | 4.7  |  4  |  9  |         
30 Aug 96 | N V    1238 | 5.25 | 17.  |  4  | 14  |         
30 Aug 96 | O V     629 | 5.37 | 3.7  |  9  | 14  |         
30 Aug 96 | Mg X    624 | 6.05 | 8.0  | 12  |  ?  |         
30 Aug 96 | Fe XII 1242 | 6.14 | 4.6  | 11  |  ?  |  [3]

Remarks:
[1] blended with 2 Å Continuum
[2] blended with Si VIII
[3] corrected for blends

yellow=chromosphere, orange=transition region, red=corona

IED, 19 Jul 02