Subject: AstroAlert: Major X-Class WHITE-LIGHT Solar Flare Alert - 06 June
Date: Tue, 6 Jun 2000 23:42:11 -0600 (MDT)
A s t r o A l e r t
Sun-Earth Alert
Solar Terrestrial Dispatch
http://www.spacew.com Link
06 June 2000
* Major X-Class WHITE-LIGHT Solar Flare Alert *
* Stereo Movie of X-Class Flare *
Detailed images, movies and resources available at:
http://www.spacew.com/astroalert.html
(We apologize for the delay in posting this. It has taken a while to
assemble the resources together after performing all the post-flare
analyses that are required.)
Active sunspot region number 9026 produced a flurry of very energetic
solar activity on 06 June. Two X-class flares occurred between 13:10 and
17:00 UTC (9:10 am and 1:00 pm EDT) on 06 June. The largest X-class flare was
an enormous X2.3 x-ray event. In the light of hydrogen, the flaring region
covered an area so large you could fit roughly 30 times the entire surface
area of the Earth within it.
Today's most powerful X2 solar flare was a rare WHITE-LIGHT flare.
A white-light flare is a brightening of the visible photospheric surface of
the Sun. Anyone observing the Sun with a simple telescope equipped with a
filter that cuts down the brightness of the Sun to safe levels could have
observed this event. It occurred at 16:06 UTC and lasted a couple of minutes
just as x-rays were increasing to X-class levels. Images and even a movie
of this event were captured by Antonio Sanchez-Ibarra at the University of
Sonora (Estacion de Observacion Solar [EOS]) using a CCD video camera at the
continuum. A movie of this event is available at:
http://cosmos.cifus.uson.mx/eosdata.htm link. We congratulate the group there at
EOS for a job well done in capturing this event!
An enormous coronal mass ejection, part of which is headed toward the
Earth, was observed in conjunction with today's major flare activity. Images
and movies of the progress of the halo coronal mass ejection are available at
the URLs: http://www.spacew.com/astroalert.html Link and:
http://www.spacew.com/c2 or: http://www.spacew.com/c3. The velocity of the
coronal mass ejection was clocked to near 1,200 kilometers per second (4.3
million kilometers per hour or 2.7 million miles per hour) by measuring the
radio emissions created by the supersonic shockwave of the disturbance as it
travelled outward through the inner part of the solar corona.
This Earth-directed disturbance is expected to slam into the Earth's
magnetosphere sometime during the mid-to-late UTC hours of 08 June
(mid-morning to late afternoon, Eastern Daylight Time on 08 June). The
disturbance may hit the Earth with a velocity near or in excess of 2.8
million kilometers per hour (or 1.8 million miles per hour), or about twice
the normal velocity of the solar wind.
There is a chance the pressure of the solar wind against the
magnetosphere might be strong enough to push the boundary of the
magnetosphere inside the orbit of geosynchronous satellites. The passage of
satellites into the harsher domain of the magnetosheath (which is a more
turbulent region that separates the quiet inner shell of the magnetosphere
from the solar wind) can caused some satellites to begin pointing incorrectly
at the Earth. Historically, some satellites have lost control completely and
have begun tumbling when they have crossed the magnetopause boundary.
Exposure to the more direct effects of the solar wind can also degrade the
life-span of solar arrays and other exposed surfaces. Increases in radiation
levels in space resulting from the disturbed conditions produced by the
disturbance may also result in single event upsets on spacecraft electronics
caused by surface charging anomalies. And increased atmospheric drag caused
by the ballooning of the Earth's atmosphere during increased periods of
geomagnetic and auroral activity can lower the orbital altitudes of orbiting
spacecraft. All of these effects may play a role in the upcoming events.
Auroral activity is expected to increase to storm levels on 08 and 09
June. Whether activity will become strong enough to observe from many middle
or low latitude locations won't be known for certain until after the
disturbance begins passing the Earth when spacecraft will be able to directly
sample the characteristics of the solar wind. But forecasters have a hunch
the disturbance could be moderately large, perhaps in the G2 to G4 category
range for geomagnetic storms (on a scale from G1 [minor] to G5 [extreme]).
Region 9026 does not appear to have changed very significantly following
today's major solar flare. We'll know more tommorrow, but for now it still
appears to be a potentially very volatile sunspot group. Additional major M
and X class flares are possible. And even another white-light flare may be
observed.
Among the various movies and images describing this event is one which
stands apart from the rest. The Solar Terrestrial Dispatch, in collaboration
with the Kanzelhohe Solar Observatory and the National Solar Observatory at
Sacramento Peak, New Mexico, has produced an experimental stereoscopic movie
spanning 30 minutes (or 13 frames) of the major flare observed today (a small
portion of the overall event). This is, to our knowledge, the first ever
near-realtime stereoscopic movie of a major X-class solar flare in the light
of hydrogen. Those who are interested can find it at:
http://www.spacew.com/stereo-flare.mpg Link. To see the 13 frames in stereo, look
THROUGH your monitor, forcing your eyes to focus beyond the plane of your
monitor's screen until the two solar images merge into a single stereo view
of the Sun. Tilt your head very slightly left or right, or move your head
toward or away from the monitor until the images merge into a single coherent
view of the Sun. Then (without changing focus), have your movie viewing
software begin playing the movie in a loop. It's aesthetically rather cool
and scientifically potentially valuable to produce these types of movies.
** End of AstroAlert **
-- Space Man Spiff (sm@one.of.these.days), June 07, 2000