1. Solar Interior

2. Solar Interior Energy in the sun gets out by A. circulating gases.
B. emission of photons.
C. interacting with electrons.
D. all of the above.

3. Inner Layers
The sun is mostly hydrogen with about 25% helium and small amounts of heavier elements.
At different temperatures the gases behave differently forming layers.
core
radiative zone
convective zone
photosphere

4. Equilibrium Inside the sun the gas is acted on by forces.
Gravity inward
Pressure outward
The balance is called hydrostatic equilibrium.
Density and temperature increase inside
Computer models

5. Hot Sun Surface Temperature: 5,800 K Core Temperature: 15,000,000 K
The sun produces 1027 cal/min at its surface (4  1026 W).
This is equivalent to 100 billion 1 megaton hydrogen bombs every second!!
This energy produced in the Sun flows out as light and other electromagnetic energy.

6. Core In the core all gas is ionized and forms a plasma.
Temperatures up to 15,000,000 K
Density up to 100 g/cm3
This is where fusion occurs.
photons
neutrinos

7. Radiation Layer Outside of the core is the radiation layer.
Temperature drops from 5,000,000 to 100,000 K
Still plasma
Too cool for fusion
Photons work their way out through the layer.
Absorption and re-radiation
Typically 170,000 years
photons

8. Convection Layer The highest 20% of the sun is the convection layer.
The temperature drops from 100,000 to 6,000 K.
The hydrogen and helium are a gas again with no fusion.
Energy is transferred through convection, the movement of gas to and from the surface (“hot” air rises).
photosphere
convection layer
radiative layer

9. Seismic Sun Sound waves move through the Sun like earthquakes.
Velocity ripples on surface
Probes interior
The Global Oscillation Network Group tracks solar sound waves.