1. The Sun: close-up of a spectral class G main sequence star

2. Illustration of Kirchoff’s 1st Law
A hot object emits more radiation at all wavelengths than
A cooler object (Figure 7-6)

3. Structure of a Sunspot Note granulation
Sunspots are regions of very strong magnetic field (2000 Gauss)
Demo

4. Sunspots represent “tubes” of magnetic field lines

5. This causes sunspots to often occur in pairs, with opposite magnetic poles

6. Sunspots and magnetism

7. Solar magnetic fields reach far out into space

8. The 11 Year Solar Cycle
The Sun has a “heartbeat”; its properties change on a period of 11 years

9. Latest data on this sunspot cycle

10. The Sunspot Cycle has been going on for a long time
Observations show cycle persisting, but “turning off” from 1650 to 1730 (Maunder Minimum)

11. The Structure of the Solar Atmosphere
Photosphere
Chromosphere
Corona
Temperature increases as you go up
Outermost layer flows out into space to form the Solar Wind

12. The solar corona

13. The solar corona

14. The Solar Wind A wind past the Earth at 400 km/sec
The Sun is “melting away”
Density 19 orders of magnitude less than atmosphere
A medium for solar events
May have “sandblasted” the early atmosphere of Mars

15. Explosions on the Sun: Solar Flares and Coronal Mass Ejections
The occurrence of flares and CMEs is enhanced around
The time of solar maximum

16. The Lesson for Other Stars
Do they also have sunspots, sunspot cycles, etc?
How does all this (magnetic fields, solar wind, rotation) relate to the age of a star?