Transcript Solar Observations 2 - Stanford University

Solar Observations 2
J. Todd Hoeksema
Stanford University
SOHO/MDI Magnetic Rotation
May 1998
Three-Temperature Solar Rotation
Solar X-Ray Cycle
Stellar Cycles
Hinode G-Band Image of Stellar
Surface
Flare Helioseismology
Sounds
Of Modes
SOLAR SCIENCE - Nov 07, 2006
Monster Stellar Flare Dwarfs All Others
Scientists using NASA's Swift satellite have spotted a
stellar flare on a nearby star so powerful that, had it
been from our sun, it would have triggered a mass
extinction on Earth. The flare was perhaps the most
energetic magnetic stellar explosion ever detected.
The flare was seen in December 2005 on a star
slightly less massive than the sun, in a two-star
system called II Pegasi in the constellation Pegasus.
It was about a hundred million times more energetic
than the sun's typical solar flare, releasing energy
equivalent to about 50 million trillion atomic bombs.
Fortunately, our sun is now a stable star that doesn't
produce such powerful flares. And II Pegasi is at a
safe distance of about 135 light-years from Earth.
Yet in detecting this brilliant flare, scientists obtained direct
observational evidence that stellar flares on other stars involve
particle acceleration, just like on our sun. Rachel Osten of
University of Maryland and NASA Goddard Space Flight Center in
Greenbelt, Md., presents this finding today at the Cool Stars 14
meeting in Pasadena, Calif.,,,,
This is a real image of a
typical solar flare from our
sun, from September 2005,
captured in the X-ray
waveband by NASA's TRACE
satellite. Note the bright
magnetic loops of matter. The
twisting and reconnecting of
these loops initiate the flare.
NASA's Swift satellite
detected a similar flare from a
star system called II Pegasi
135 light-years from Earth...
except it was one hundred
million times more energetic
than the sun's typical solar
flare. Had it been from our
sun, it would have triggered a
mass extinction on Earth. The
II Pegasi flare was too distant
(fortunately) to image in
detail. Credit: NASA/LMSAL
Hinode Trilobite - Still
Hinode Stellar Atmosphere - Still
Star Spots
Multi-color observations of Star Spots
Multi-Instrument SOHO Sun
SOHO 10th Anniversary Spectacular
Comet Tail Disruption
Comets in the Solar Wind
Solar Observations 2
J. Todd Hoeksema
Stanford University