1. STELLAR EVOLUTION – THE STANDARD SOLAR MODEL AND SOLAR NEUTRINOS – MARIE ZECH

2. Content: 1.Our sun – basic facts 2.SSM – the Standard Solar Model 1.What is the SSM? 2.Helioseismology 3.The solar abundance problem 3.Solar Neutrinos 1.What is a neutrino/ solar neutrino? 2.Detection of neutrinos 3.Solar neutrino problem 4.Neutrino oscillation 4.Summary 5.Sources Marie Zech2

3. 1. Our Sun - Basic Facts  G –type main sequence star  yellow dwarf  diameter: 109 x Earth  mass: 330,000 x Earth  Population I: heavy element rich star  temperature  in the core: up to 15.7 million K  on the surface: ≈ 5,800K Marie Zech3 Hydrogen73.46% Helium24.85% Oxygen0.77% Carbon0.29% Iron0.16% Neon0.12% Nitrogen0.09% Silicon0.07% Magnesium0.05% Sulfur0.04% composition of our sun:

4. 1. Our Sun – Basic Facts  formed ~4.567 billion years ago  formation may have been triggered by nearby supernovae  NOW:  roughly middle aged  will remain fairly stable  FUTURE:  red giant  becomes very large Marie Zech4 http://www.nasa.gov/images/content/171926main _heliolayers_label_lg.jpg

5. 2. The Standard Solar Model Marie Zech5

6. 2. The Standard Solar Model Marie Zech6

7. 2. The Standard Solar Model Marie Zech7 figure d: dependence of electron number density upon solar radius

8. 2. The Standard Solar Model Marie Zech8 Properties of the solar model as a function of time

9. 2. The Standard Solar Model 2.2 Helioseismology:  study of solar seismology  provides information about the interior of the body  the surface of the sun is filled with patches that oscillate  the sun oscillates in three dimensions  rich spectrum of frequencies  these frequencies provide information about temperature and density distribution within the sun and it´s chemical composition Marie Zech9 https://www.spaceinn.eu/project /science/helioseismology/

10. 2. The Standard Solar Model Marie Zech10

11. 2. The Standard Solar Model Marie Zech11 GS98 – high metallicity AGSS09 – low metallicity

12. 2. The Standard Solar Model Marie Zech12 SSM characteristics compared to helioseismic values

13. 3. Solar Neutrinos 3.1 What is a neutrino?  lepton, charged neutral  3 flavours:  electron neutrinos  muon neutrinos  tau neutrinos  solar neutrinos are created in the core by nuclear reactions  neutrino fluxes are sensitive to the core temperature Marie Zech13

14. 3. Solar Neutrinos Marie Zech14

15. 3. Solar Neutrinos Marie Zech15 estimated neutrino fluxes of different SSMs

16. 3. Solar Neutrinos 3.2 Detection of neutrinos  cannot be detected directly  detector are often build underground for protection from cosmic rays and background radiation  90ies: Super Kamiokande in Japan  50,000 t Water – Cherenkov – detector  can´t distinguish between different neutrino flavours  1999 – 2006 Sudbury Neutrino Observatory in Canada  heavy water  possible to differ between muon and tau / electron neutrinos via statistics Marie Zech16

17. 3. Solar Neutrinos Marie Zech17 http://www-sk.icrr.u-tokyo.ac.jp/sk/gallery/wme/sk_01h- wm.jpg https://www.snolab.ca/sites/default/file s/images/SNO-hi%20res.preview.jpg Super KamiokandeFish-eye photo of the SNO Detector

18. 3. Solar Neutrinos 3.3 Solar neutrino problem  pattern of fluxes in contrast to SSM predictions  significant deficit of electron neutrinos and muon neutrinos  day/ night differences (upward going Neutrinos in detector) Marie Zech18 http://www-sk.icrr.u-tokyo.ac.jp/sk/sk/neutrino-e.html

19. 3. Solar Neutrinos 3.4 Neutrino Oscillation  quantum mechanical interference phenomenom  flavour of neutrino can change while „flying“  probability of this change can be calculated  solution to solar neutrino problem: missing neutrinos changed e.g. into not with Kamiokande or SNO detectable tau neutrinos  NEW: neutrinos are not without a mass  new physics aside from standard model of astrophysics needed Marie Zech19 http://www-sk.icrr.u- tokyo.ac.jp/sk/sk/neutrino-e.html superposition of neutrino eigenstates

20. 3. Solar Neutrinos Marie Zech20 http://www.nobelprize.org/nobel_pr izes/physics/laureates/2015/images/ kajita-photogallery.jpg https://www.snolab.ca/news/2015-10-15-canadian- scientist-shares-nobel-prize-win-physics-sno- experiment Winners of the Nobel Prize 2015 in Physics Arthur B. McDonald Takaaki Kajita

21. 4. Summary  data from low Z abundance SSM showd in comparison to helioseismic data inconsistencies  to check data: neutrino fluxes  not as much neutrinos were detected as calculated → solved by neutrino oscillation (change of neutrino flavour is possible) → new kind of physics is needed, standard model of astrophysics is not entirely correct Marie Zech21

22. 5. Sources:  Annu. Rev. Astron. Astrophys. 2013.51:21-61  Bahcall, John N: Neutrino Astrophysics, Cambridge University Press, 1989  Physik Journal 14 (12), WILEY-VCH Verlag GmbH&Co.KGaA, Dezember 2015  https://www.snolab.ca/  http://www-sk.icrr.u-tokyo.ac.jp  https://en.wikipedia.org/wiki/Sun  https://en.wikipedia.org/wiki/Solar_neutrino  https://en.wikipedia.org/wiki/Neutrino Marie Zech22