Solar Observations 2

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Solar Observations 2

• J. Todd Hoeksema
• Stanford University

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SOHO/MDI Magnetic RotationMay 1998
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Three-Temperature Solar Rotation
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Solar X-Ray Cycle
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Stellar Cycles
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Hinode G-Band Image of Stellar Surface
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Flare Helioseismology
Sounds Of Modes
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• 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
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Hinode Trilobite - Still
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Hinode Stellar Atmosphere - Still
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Star Spots

• Multi-color observations of Star Spots

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Multi-Instrument SOHO Sun
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SOHO 10th Anniversary Spectacular
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Comet Tail Disruption
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Comets in the Solar Wind
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Solar Observations 2

• J. Todd Hoeksema
• Stanford University