1. The Sun, Our Star

2. Radius = 7x108m or 109 Earth radii Mass = 2 x 1030 kg or
Size & Structure
Radius = 7x108m or
109 Earth radii
Mass = 2 x 1030 kg or
333,000 Earth masses

3. Planets, to correct relative size

4. Artist’s view of the Solar System
Figure 7.1

5. Sketch of Oort cloud and Kuiper belt
Figure 7.4

6. Distance = 1.5 x1011m from Earth Temperature
Surface 5780 K or 9900 °F
Core 1.5x107K or 2.7x107°F

7. Composition
All in gas form
71% Hydrogen
27% Helium
2% other

8. Distance from triangulation Mass from orbits
How do we know?
Temp. from color
Distance from triangulation
Mass from orbits
Interior temp. from power output

9. A simple way to measure the Sun’s diameterB

10. Energy generating in core from fusion; photons emitted
Interior
Energy generating in core from fusion; photons emitted
Carried thru Radiative zone
Bcs of density of atoms takes photon over 100,000 years

11. Outer region (Convection core) less dense gas (hotter) rises to suface

12. Hydrostatic Equilibrium
Gravity (immense mass) cause Sun to want to collapse on itself
Pressure from rapid motion (hot gas) of atoms balances this

13. Figure 11.8

14. Maintaining the Pressure
E=mc2
Mass can be turned directly into energy
Mass of size of a pill turned into energy would equal that of a nuclear bomb

15. Hydrogen into Helium yields a lost mass (mass deficit)
Nuclear Fusion
Hydrogen into Helium yields a lost mass (mass deficit)
Possible because of heat & pressure of Sun

16. Hydrogen and helium atoms and isotopes
Figure 11.10

17. Diagram of proton-proton chain
Figure 11.11 A B C

18. Proton Proton chain Step 2
2 H collide to become a heavier H
Step 2
The Neutron Proton collides with a single H and becomes He and emits a photon (light) and energy

19. Step II
The Neutron Proton collides with a single H and becomes He and emits a photon (light) and energy

20. Step III
2 3He combine to from a 4He ,2 1H and energy

21. Neutrinos
Difficult to measure
No charge little mass
Pass thru matter
Tanks of heavy water miles under ground
If electron is hit it emits photon

22. Magnetic fields
Sun spots – regions that differ in color due to magnetic fields and temp
Blocks heat

23. How magnetic fields cause sunspots
Figure 11.15

24. Responsible for comets
Solar wind
Responsible for comets
Loss of mass from protons & electrons that escape gravitational pull of Sun

25. Solar differential rotation
Figure 11.22