1. 1 THE SUN Nada Al-Haddad KU Leuven SHINE 2011

2. 2 OUTLINES Properties Core Radiative Zone Convective Zone Photosphere Chromosphere Corona 2

3. 3 Main Sequence G star M = 2x10 30 kg R = 7x10 8 m = 7x10 5 km L = 3.9x10 26 W (Solar Constant = 1350 W/m 2 ) Mean Density = Mass/Volume = M/((4/3)πR 3 )= 1400 kg/m 3 = 1.4 g/cm 3 Properties 3

4. 4 Main Regions 4

5. 5 The core Energy generation through nuclear burning 5 Main Regions

6. 6 Adapted from George Rafflet at Jigsaw, India 2007 The core Energy generation through nuclear burning 6 Main Regions

7. 7 Radiative Zone Energy transportation through Radiation 7 Main Regions

8. 88 Convective Zone Energy transportation through Convection

9. 9 Convective Zone Energy generation through nuclear burning 9 Main Regions

10. 10 Photosphere Source of Photons 6000 K SUNSPOTS Low temperature in the photosphere ~ 4780 K Intense magnetic field Days-Weeks Features: 10

11. 11 1600 Km 10^-4 the intensity of the photosphere Temperature increase 4400-100000 K He II, Fe II, Si II, Cr II and Ca II Chromosphere Features: Flares Prominences 11

12. 12 Transition region 12

13. 13 Corona Very high temperature Visible at total eclipse No well defined outer boundary Low density 5273 K 2,000,273 K Features: Coronal holes Dark in X-ray and EUV Low density High speed Solar wind 13

14. 14 Solar wind Constant stream of charged particles (Plasma) from Sun to beyond pluto ( 5900 million km) 95% protons & electrons, 5% isotopes: helium-3, helium-4, neon-20, neon-21, neon-22, and argon-36 Average speed 450 km/s Average Density 4 atoms/cm 3 Shapes the magnetosphere 14

15. 15 Solar wind Constant stream of charged particles (Plasma) from Sun to beyond pluto ( 5900 million km) 95% protons & electrons, 5% isotopes: helium-3, helium-4, neon-20, neon-21, neon-22, and argon-36 Average speed 450 km/s Average Density 4 atoms/cm 3 Shapes the magnetosphere 15

16. 16 Solar Cycle 16

17. 17 Solar Cycle

18. 18 Coronal Mass Ejections explosions in the Sun's coronacorona huge bubbles of gas threaded with magnetic field lines 10^6 K A lot of material is thrown out into the solar windsolar wind CME's can seriously disrupt the Earth's environment Earth's environment 18

19. 19 Dank U Wel! 19