Solar Interior

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 radiativelayer

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.