Mittwoch, 13. Dezember 2006
Polarlichtwarnung für den 14./15.12.06
Heute morgen um 02:41 UTC ist bei der zentralen Sonnenfleckengruppe (Region 930) erneut ein grosser X-class Flare aufgetreten. Die durch dieses Ereignis entstandene Coronal Mass Ejection (CME) dürfte die Erde bereits im Laufe des morgigen Tages erreichen und möglicherweise Polarlichter am Abend des 14. und evtl. 15. Dezembers auslösen. Es lohnt sich also, in den kommenden Nächten Ausschau danach zu halten.

Bereits am 5.12. hat die selbe Gruppe einen massiven X9 Flare erzeugt. Damals lag die Fleckengruppe aber am Sonnenrand, so dass der CME die Erde nicht frontal traf. Diesmal sieht es aber anders aus (siehe nachfolgende Aufnahme im Weisslicht):

Sonnenflecken am 13.12.06

Hier noch der Originaltext der Alert-Message:

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This Is SKY & TELESCOPE's AstroAlert for Sun-Earth Interactions
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A s t r o A l e r t
Sun-Earth Alert

Solar Terrestrial Dispatch
http://www.spacew.com

13 December 2006


ALERT FOR POSSIBLE STRONG AURORAL ACTIVITY - 14-15 DEC 2006

After stabilizing during the last week, active sunspot Region 930 began
growing again during the last 24 hours. Rapid growth in the southeastern
quadrant of the spot cluster resulted in a significant increase in magnetic
shear - a component required to produce energetic solar flare activity. At
02:41 UTC on 13 December, this active region spawned another major X-class
solar flare. This event, rated a class X3.4 event, included some intense
radio emissions and was also responsible for accelerating energetic protons
to near relativistic velocities. Only about 5-minutes after solar x-rays
reached a maximum, these very energetic protons began arriving at the Earth.
Their energies were strong enough to enhance radiation levels in the polar
regions at ground levels for a few hours in what is known as a Ground Level
Event (or GLE). The enhanced radiation does not pose a health hazard for
populations outside of the polar zones, although it is possible some
transpolar aircraft flights may have needed to be rerouted or reduced in
altitude for a time following this event (we have no confirmation of such
actions at the present time).

The coronal mass ejection thrown out by this energetic event is expected
to impact the Earth during the early to mid-portion of the UTC day of 14
December. For residents in North America, this is equivalent to the late
evening and early morning hours of 13/14 December. When this disturbance
impacts, and for approximately 18 to 24 hours thereafter, there is a good
chance auroral activity ("northern lights") will intensify to levels that
will permit observations from widespread mid-latitude (and perhaps even lower
latitude) locations. All of the mid-U.S. states may observe periods of
activity on 14 December if this disturbance arrives or lasts sufficiently
long to be observed during a favorable portion of the night. If no activity
is oberved on 14 December, try again on 15 December. Whether activity is
observed beyond the 15th will depend on whether Region 930 spews out
additional energetic events.

The auroral activity watch issued for this time period follows below.

MIDDLE LATITUDE AURORAL ACTIVITY WARNING
Updated: 06:15 UTC on 13 December 2006
Solar Terrestrial Dispatch
www.spacew.com


VALID BEGINNING AT: 00:00 UTC ON 14 DECEMBER
VALID UNTIL: 23:00 UTC (5 pm EDT) ON 15 DECEMBER

HIGH RISK PERIOD: 14 DECEMBER (UTC DAYS)
MODERATE RISK PERIOD: 14 - 15 DECEMBER

PREDICTED ACTIVITY INDICES: 15, 70, 30, 15 (13 - 16 DECEMBER)

POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: HIGH

POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 12 HOURS
MINOR BELT = 12-24 HOURS

ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR AND AFTER LOCAL MIDNIGHT

EXPECTED LUNAR INTERFERENCE: MODERATE AFTER LOCAL MIDNIGHT

OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: GOOD TO VERY GOOD

AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
(THIS LINE IS VALID *ONLY* IF FAVORABLE STORM CONDITIONS OCCUR)

NORTHERN CALIFORNIA TO NORTHERN NEVADA TO COLORADO TO KANSAS TO SOUTHERN
MISSOURI TO TENNESSEE TO NORTH CAROLINA.

ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
(THIS LINE IS VALID *ONLY* IF FAVORABLE STORM CONDITIONS OCCUR)

FRANCE TO NORTHERN ITALY TO AUSTRIA TO SOUTHERN POLAND TO CENTRAL RUSSIA.

NEW ZELAND AND SOUTHERN AUSTRALIA MAY ALSO SPOT PERIODS OF ACTIVITY
MODERATE TO STRONG ACTIVITY.

SYNOPSIS...

A powerful and well-directed solar flare from active solar Region 930
was observed early on 13 December. This event has the potential to produce
periods of moderate to strong (possibly even intense) auroral storm activity
on 14 December, possibly lingering into 15 December. The most intense phase
of activity is likely to occur some hours after the initial impact, which is
currently expected near 07:00 UTC on 14 December (2 am EST on 14 December).
The moon will begin to impinge on observations after it rises sometime after
local midnight, so the best observations (if possible) will occur prior to
and near local midnight when the moon is still below the horizon.

This warning will remain valid through 24:00 UTC (5 pm EST) on
15 December. It will be updated or allowed to expire at that time. For
updated information, visit: http://www.spacew.com/aurora/forum.html. For
real-time plots of current activity, visit: http://www.spacew.com/plots.html

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