TEST – check syllabus. Wed Oct 22 306 Tier 6pm

1. TEST – check syllabus. Wed Oct 22 306 Tier 6pm Topics: From the 1st day up to and INCLUDING THE SUN Images: will be in black and white on the test. Practice Questions: pick questions related to lectures in Mastering Astronomy Conflicts with NON-DEFERRED tests – see updated syllabus online and talk to me after class in the hall. For exam security, students will not be able to leave the test room until ~ 6:45pm. • If you bring a non-programmable calculator then it can only be one of the following: • Sharp EL-240SAB • - Sharp EL-510RNB • - TI-30XZ • - TI-30X IIS

2. Term test: Wednesday Oct 22. Bring Pencils & Erasers! The movie of images will loop – you will see each image a few times. • See the review notes for the test at http://www.physics.umanitoba.ca/~english/2014fallphys1810/test.html available from the public website for the class. • Work and answer on the question sheet - this way I can give you a mark if you make a mistake on the bubble sheet. • Hand ALL materials in – make sure your name and student number is on everything. Class attendence   mark 

3. Common examples of academic dishonesty that occur every term: • A student brings a calculator to the final exam. The calculator is allowed by the instructor, but the calculator cover is forbidden. • An invigilator discovers the notes and the incident is forwarded to the department Head or the Associate Dean. An act of academic dishonesty has occurred regardless of whether the notes are used by you during the exam. • Also when handing in materials you write on your exam materials near other students answer sheets this provides an opportunity for academic dishonesty. • What are the consequences of the penalties? • They may slow down the progression of your degree, costing you time and money. • They may be visible to potential employers, professional school applications, or graduate schools. • They may affect your student visa eligibility for a year or more. • Protect yourself: • Do not bring unauthorized material into the exam (e. g. notes, cell phone, calculator cover). • Resist opportunities to collaborate inappropriately or look at someone else’s paper. • If you suspect someone looking over your shoulder … Cover your paper; ask to be moved to another seat; alert the invigilator. • Review the online tutorials available through Student Advocacy: • umanitoba.ca/student/resource/student_advocacy/AI-and-Student-Conduct-Tutorials.html

4. Cheating ... on tests, quizzes, exams, or midterms • Cheating can be spontaneous or premeditated. • You are also cheating if you allow others to look at your exam. • The Faculty of Science values academic Integrity. Cheating will not be tolerated by the Faculty of Science. • Penalties may include a minimum of: • zero in the assignment, • F-DISC in the course, • a notation written on your transcript, and/or • suspension from courses in the department or the Faculty of Science for one year.

5. Lecture 18: Sun • Read before coming to class • Stars Chapt 17 • flux, luminosity, magnitudes, spectra • Hertzsprung-Russell Diagram Coronal Sun “Moss” Hi-C camera: Credit: R. Morton / H. Morgan

6. The Sun Image: Jim Lafferty • Hα • Inverted: black == bright

7. The Sun • Below: convection zone, radiation zone, and core. • Above: solar atmosphere with chromosphere, transition zone, and corona

8. The Sun’s Core Read in your text – 16.6. Thermonuclear Fusion Proton-Proton Chain  anti-matter  energy (gamma-rays)  neutrinos  H, He (Deuterium)

9. Figure 16-9Astronomy Today The Sun’s Interior: Transportation of Energy Outwards • Radiation Zone: • Ionized state. • core generates photons ( ) & heat • absorbed by atoms until all ionized • travel freely near core

10. Figure 16-9Astronomy Today The Sun’s Interior: Transportation of Energy Outwards • Convection Zone: • Excited state. • T lower • --> e- recombine with atoms & absorbed. • opaque since not escaping. Photosphere: Less dense so can escape. Radiation again.

11. Figure 16-9Astronomy Today The Sun’s Interior: Transportation of Energy Outwards • Neutrinos escape from core in seconds to minutes. • absorbed and re-emitted repeatedly •  ~170,000 yrs for to escape. lose energy  yellowish rather than gamma-ray

12. The Sun’s Surface Figure 16-10Solar Granulation of the Photosphere

13. The Sun’s Surface KIS/SVST (La Palma) • granules: • diameters: ~250 km to > 2000 km; average 1300 km. • Lifetimes 8 to 15 min • velocities of gas 1 to 2 km/s.

14. Table 16-1The Standard Solar Model • core (where energy is produced) is hot • sun cools with distance from this engine. • Unexpectedly atmospheric T increases with distance! Probably caused by disturbances in the Sun’s magnetic field.

15. Upper Chromosphere Same day at optical wavelengths. • UV at 304 angstroms (A). • 60,000 C. • some activity correlates with sunspots.

16. Corona at Height Above the Chromosphere • 171 A • T ~ 1 million C

17. Higher in the Corona • 195 A • 1.5 million C

18. Upper Corona • 284 A • 3 million C

19. UV of Corona • 171 A, 195 A, 284A.

20. Activity in the Atmosphere is Related to Sunspots on Photosphere.

21. Sunspots Helioseismology --> depth • Dark since cooler T (4500K) than surrounding photosphere (5800K). • Spectra  magnetic field (B) is 1000x photosphere. • Sunspots’ B interfere with flow of hot gas towards the surface  cooler sunspot.

22. Sunspots: Differential Rotation • By observing sunspots • gas at equator rotates once ~ 25 days. • Gas at poles rotates once ~ 30 days.

23. Sunspots TRACE satellite • Sunspots in pairs, linked by B lines. • Superheated gas (plasma) flows along B lines forming

24. Spicules • B tubes filled with gas jetting into chromosphere. • Associated with active regions (e.g. left sunspot) • Probably due to churning in Sun’s outer layers. • Help heat atmosphere? • movie via APOD – link on class website

25. Generating Sunspots SOHO/ESA/NASA • Twisting in global B is caused by • differential rotation with latitude. • convection of the magnetized gas. Dynamo  B

26. Sunspot Cycle • This cycle of B wrapping, unwrapping and starting to wrap again takes roughly 11 years.

27. Prominences • Loops or sheets of plasma trace the B lines in or near sunspots. • Extensions up to 10 times the diameter of Earth. • Last for days or weeks.

28. Prominence (Solar Dynamic Observatory)

29. Solar Flares and Coronal Mass Ejections • Green: solar flare -- also seen in X-ray (100 million K) • Flash across region in mins & blast into space. • Red: coronal mass ejection • Giant magnetic bubbles of ionized gas separating from the solar atmosphere. • Occur weekly at sunspot mininum & a few times a day at maximum. • Blue: proton shower – recall fast moving particles are called cosmic rays.

30. Corona • Promeninces • APOD – APOD link on our webpage

31. Solar Wind • Continous stream of electromagnetic radiation and cosmic rays. • from high in corona where gas is hot enough to escape. • From coronal holes – regions where magnetic field loops snap and extend into space.

32. The Realm of Belief: The World Will End 2012 SOHO/ESA/NASA • Some 2012 fears are related to solar activity at the peak of sunspot activity. • The peak occurred in 2013 (not 2012).

33. Earth’s Magnetosphere: Illustration • The Earth's B is complicated and will protect life even if a polarity shift was occurring. • However solar activity does disrupt satellite communications and power networks.

34. Influence of the Sun: The edge of the Solar System • Solar Wind: • plasma • about 1.5 million km per hr. • Heliosphere: The solar wind forms a large plasma bubble as the sun orbits in our Galaxy. • Heliopause: Estimated between 120 to 150 AU then ISM.

35. Sun’s Influence: On Earth • The sun’s luminosity • equivalent to 10 billion 1-megaton nuclear bombs per second. • intrinsic • Solar Constant == flux

36. Material for mid-term up to here.