Weekly Notes from the Yohkoh Soft
X-Ray Telescope (Week 47)
21-Nov-97 23:00 UT
Instrument Status
The Soft X-ray Telescope remains in fine working order.
During this week, we spent most of our time observing AR 8108, which
was also a target of the SERTS '97 rocket (launched on 18 November 19:35 UT).
The region was highly eruptive, and even a short-lived flare gave us
an impression that the loop structure was lifting up.
A more detailed report of this week's activities is
available here.
Observation of the Week
We supported the SERTS 1997 flight on 18 November 1997 by keeping the
data between 19:37 and 19:57 UT from being overwritten. The following
picture is an SXT full-disk image around the time of the SERTS launch.
The box shows the field of view of SXT partial frame images (220000 km
square).
(Click on the picture to see a larger, more visible, version.)
In the following, SXT partial frame images are displayed. In order to
disentangle the line of sight differential emission measure, we ran a
four-filter sequence. Note that this active region, AR 8108, shows us
even in the thickest (Beryllium) filter. The field of view is
220000 km square.
AR 8108 produced a number of C class flares. One of them was on
17 November 1997 at 15 UT. Although its soft X-ray light curves
show a slow decay, it seems to have an impulsive component which
is rather short-lived. The following movie, taken before the slow
decay started, gives us an impression that soft X-ray loops were
moving up.
ftp://isass0.solar.isas.ac.jp/pub/sxt_co/17-NOV-97_g.gif
Another event was an LDE on 19 November. The following mpeg movie
shows expanding loops/eruptions in NW and SE well before the flare.
After the flare onset, a cusp structure is clearly seen.
ftp://isass0.solar.isas.ac.jp/pub/sxt_co/lde_971119_18_ffi.mpg
Further analysis of these events is ongoing.
Nariaki Nitta 21-Nov-97 (email nitta@isass0.solar.isas.ac.jp)