1. Zachary Robinson Phys 406

2.  What creates the sun’s energy? ◦ Composition of Sun ◦ Fusion in the Sun (and other stars)  Creation of the elements  Studying the sun with helioseismology ◦ What is it? ◦ How is it used?  Studying the sun through neutrino detection ◦ Solar neutrino problem ◦ SNO

3.  74% Hydrogen  24% Helium  2% Trace Elements http://www.nasa.gov/images/content/449080main_img_feature_1650_4x3_946 -710.jpg

4. Hydrogen Recycling: Images from: http://www.nobelprize.org/nobel_prizes/physics/articles/fusion/ http://www.nobelprize.org/nobel_prizes/physics/articles/fusion/

5. Images from: http://www.nobelprize.org/nobel_prizes/physics/articles/fusion/ http://www.nobelprize.org/nobel_prizes/physics/articles/fusion/

6. Positron

7.  Video from NOVA’s “Origins” mini-series:  http://www.youtube.com/watch?feature=play er_embedded&v=neMEo8ZrwuI http://www.youtube.com/watch?feature=play er_embedded&v=neMEo8ZrwuI

8.  What is it? ◦ Study of the interior of the sun via observations of sound waves on its surface  How does it work? ◦ Sun acts as a spherical resonant cavity for acoustic waves ◦ Oscillations from acoustic waves result in small Doppler shifts of spectrum lines

9.  How is it used? ◦ By numerically solving solar models we can determine information about the sun  For example: Solar structure, chemical composition, temperature at different depths http://www.stat.berkeley.edu/~stark/Seminars/Aaas/helio.htm

10.  Detecting the proper amount of neutrinos from the sun would verify fusion theories  Solar Neutrino Problem (SNP): ◦ Solar neutrino measurements have yielded inconsistent and perplexing results ◦ Presently the measured flux of neutrinos is significantly less than the expected output from the sun’s fusion reactions!  SAGE and GALLEX detect only 60 to 70% of expected http://www.chemistry.bnl.gov/SciandTech/SN/

11.  The sun’s reaction mechanisms are not correctly understood ◦ This would be a huge blow to models which have otherwise been very successful ◦ No satisfactory modifications have been proposed  Experiments could be performed incorrectly  Reaction rates in the Sun could be lower than calculations predict  Something could happen to the neutrinos in transit to earth…

12.  Three types of neutrinos: ◦ Electron, muon, tau  The sun should only produce electron neutrinos  Until recently, neutrino detectors could only detect electron neutrinos  MSW effect: Sun’s high mass densities enhance the flavor oscillations of neutrinos conferences.fnal.gov

13.  Detector that could detect all three flavors  Built 6800 feet underground in Canada  Cherenkov detector using 1000 metric tons of heavy water (D 2 O)  All air, water, and materials in detector are extremely pure to reduce background noise from radioactive elements  Collecting data since 1999 http://www.sno.phy.queensu.ca/images/man_on_deck.GIF

14. "Fusion Process of the Sun." Grant Chronicles. GrantChronicles.com, 2009. Web. 28 Nov 2011.. Guenther, D.B. "Age of the Sun." Astrophysics Journal. 339. (1989): 1156- 1159. Print. Graps, Amara. "Helioseismology." Stanford.edu. Stanford University, 19 Feb 2009. Web. 6 Dec 2011.. "How the Sun Shines". Nobelprize.org. 30 Nov 2011 http://www.nobelprize.org/nobel_prizes/physics/articles/fusion/ Stark, P.B.. "Sounding the Sun: Helioseismology." AAAS Seminars. University of California, Apr 2011. Web. 3 Dec 2011. Strobel, Nick. "Neutrino." The Sun and Stellar Structure. AstronomyNotes.com, 12 Jun 2010. Web. 3 Dec 2011. "The SNO Homepage." The Sudbury Neutrino Observatory. The SNO Institute, 21 Apr 2011. Web. 24 Nov 2011..