The Sun as the prime example of stellar structure and evolution

The Sun

Close-up of a G2 Main Sequence Star

Stellar Interior

The Solar Interior…the prime application of the equations of stellar

structure

Density in the solar interior

Temperature in the Solar Interior

The “Faint Young Sun Paradox”

The Neutrino Sun

Solar Neutrino Experiments

Helioseismology: Eigenmodes of the Sun

The Solar Atmosphere

Layers of the Solar Atmosphere

• Photosphere

• Chromosphere

• Corona

Granules in the Solar

Atmosphere

The Chromosphere-region of partially ionized hydrogen

The Solar Corona

What is it? How did it get that way?

Corona shines at level of one millionth the photosphere. It is Thompson scattered

sunlight

To understand astronomical objects, astronomers take

spectraThe spectrum of the corona reveals

its most interesting characteristic

The dominant ionization state depends on the temperature…

example N

The X-Ray Sun

The Temperature Profile in the Solar Atmosphere

The key to understanding the corona is the solar magnetic field

Above the corona: direct magnetometer measurements

in the solar wind

The Flowing Medium of the Solar Wind