SOHO/UVCS CME watch program in support of the Sigmoid JOP 106 during the WSM III Campaign:
Position Angle: 292 degrees
Heights: 1.7 Ro, 2.3 Ro, 2.6 Ro
Exposure time: 1.7 Ro: 1000 sec
2.3 Ro: 300 secObservation sequence: repeating the (1.7 Ro, 2.3 Ro, 2.6 Ro) sequence
2.6 Ro: 200 sec
O V] 1218 A
O VI 1032 A, 1037 A
Si XII 499 A
N III 989 A, 991 A
C III 977 A
Mg X 609 A
A brief, preliminery description of the SOHO/UVCS
observations on the west limb jet/CME on Aug. 26, 1999:
SOHO/UVCS caught a CME at the NW limb during the sigmoid
JOP106 on Aug.26 from 21:37 UT to 23:15 UT at 1.7 Ro. It is still not clear
right now if this CME comes from the active regions where the sigmoid resides.
A preliminary look at the data shows brightening at Lyman Alpha, Lyman
Beta, C III 977, N III doublets @989/991, OVI doublets @1032/1037 and
possibly O V] 1218. These lines were blue-shifted, then turned red-shifted.
There is no obvious sign of CME-associated materials at 2.3 and 2.6 Ro.
CDS also observed a jet at 21:09 UT at the NW limb!
More details on the line shifts--
At 1.7 Ro, UVCS saw lines blue-shifted from 21:37 to 21:55,
~no shift from 22:06 to 22:24, red-shifted from 22:35 to 22:53, more red-shifted
from 23:04 to 23:15. From the CDS
data , O V 609 (and He I too) is red-shifted @21:09, blue-shifted
only at the base @ 21:34 and blue-shifted @21:59. The time sequence of
the line shift seems correlate well with ~30 minutes travelling time
from the limb to 1.7 Ro, but the direction of the line shift is reversed!
Lyman alpha line is narrower than the background coronal Lyman alpha, not
broadened as what is shown for O V of the CDS data. Our O V] 1218
line seems brightened too, but we have to be careful to substract LyA grating
ghost in our data.