Classroom Presentation about the Sun

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Sunspots

Typically about 10000 km across

• At any time, the sun may have hundreds or none

• Dark color because they are cooler than photospheric gas (4500K in darkest parts)

• Each spot can last from a few days to a few months

• Galileo observed these spots and realized the sun is rotating differentially (faster at the poles, slower at the equator)

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Sunspots & Magnetic Fields

•The magnetic field in a sunspot is 1000x greater than the surrounding area

•Sunspots are almost always in pairs at the same latitude with each member having opposite polarity

•All sunspots in the same hemisphere have the same magnetic configuration

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SOLAR MAGNETOGRAM 11/13/12

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The Sun’s differential rotation distorts the magnetic field lines

The twisted and tangled field lines occasionally get kinked, causing the field strength to increase

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Sunspot Cycle

Solar Cycle is 22 years long – direction of magnetic field polarity flips every 11 years (back to original orientation every 22 years)

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Heating of the Corona

v Charged particles (mostly protons and electrons) are accelerated along magnetic field “lines” above sunspots.

v This type of activity, not light energy, heats the corona.

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Charged particles follow magnetic fields between sunspots: Solar Prominences

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Solar Prominence

Typical size is 100,000 km

May persist for days or weeks

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The Sun November 14, 2011

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