1. Today’s Comments Graded papers – see Raquel to get old papers or tests. Grades updated yesterday Lab Students: pickup notebooks this week; grades on website D2L Quizzes 9&10 available; do them to prepare for test 3 Observations –Binoculars available for Moon Craters on your own. Fill out loan form. RETURN BINOCULARS BY RETURN DATE –Sunset Part 2. Work on this. Due Apr. 28 –Telescopes, Star Gazing & Moon Craters available at UMN, Macalester and Eagle Lake Observatory – see dates on calendar Apr. 24, 25, 28 & May 1 –Space Exhibit at Science Museum of MN on 5:30-9pm, Thursday, May 7; Evite invitation coming tomorrow and you need to RSVP Answer EVITE – if you didn’t get this, see Raquel

2. Stars Binary Stars Open Star Clusters Globular Clusters Milky Way Galaxy Other Galaxies Colliding Galaxies The Local Group Galactic Clusters

3. Binary Stars Two stars orbiting each other Very common

4. Binary Stars Important – Used to measure mass of stars (using Kepler’s Laws)

5. Binary Stars Three Main Types –Visual – see with telescope –Eclipsing – light dims periodically –Spectroscopic – Doppler shifts in spectra

6. Visual binary – See with telescope

8. Alcor A and B Mizar quadruple system Visual binary – See with telescope

9. Eclipsing binary – light dims periodically Demo at http://www.eso.org/public/usa/videos/eso1311b/ And http://www.unm.edu/~astro1/101lab/lab9/lab9_C1.html

10. Eclipsing binary – light dims periodically Kepler Telescope looks for planets this way. Over 4000 planets discovered this way. What are these planets called? Exoplanets

11. Demos at http://csep10.phys.utk.edu/astr162/lect/binaries/spectroscopic.html or http://www.unm.edu/~astro1/101lab/lab9/lab9_C1.html or https://www.youtube.com/watch?v=1kFFwHkxBiI&list=PLJistbn1hLkxuwLpuOHbt PRJFETEgu1ROhttps://www.youtube.com/watch?v=1kFFwHkxBiI&list=PLJistbn1hLkxuwLpuOHbt PRJFETEgu1RO (best: 80% of stars in binary systems) Spectroscopic binary – wobble in spectral lines

12. Open Star Clusters Few to a few thousand stars grouped by gravity in the same region of space No particular shape Generally younger stars Located in plane of galaxy Example - Pleiades

13. http://www.spitzer.caltech.edu/images/2396-sig05-023-Star-Clusters-Found-in-the-MIlky-Way

14. Pleiades M45 3000 stars ~400 LY away 13 LY across Brown dwarfs too

15. Pleiades M45 3000 stars ~400 LY away 13 LY across Brown dwarfs too

16. M39 800 LY away Cygnus

17. M7 1000 LY away 25 LY across, Scorpius

18. Perseus double cluster 7000 LY away few hundred LY across

19. http://antwrp.gsfc.nasa.gov/apod/ap070314.html

20. In Puppis M46 (upper left) 5,400 ly, 300 million years old, a few hundred stars, 30 ly across M47 (lower right) 1,600 ly. 80 million years old, 50 stars, 10 ly across. http://antwrp.gsfc.nasa.gov/apod/ap070314.html

21. Globular clusters ~100 000 stars Spherical shape Generally older stars Surround the galaxy Out of galaxy plane

22. M13 25 000 LY away, 150 LY across 12 billion yrs old http://apod.nasa.gov/apod/ap120614.html

23. Galaxy Very large collection of gas, dust and stars orbiting a central mass > 100 billion galaxies in the universe Each has millions to billions of stars

24. Milky Way Galaxy ~300 billion stars ~100 000 LY across Think fried egg shape Spiral with arms 13 billion years old http://apod.nasa.gov/apod/ap140916.html

25. http://apod.nasa.gov/apod/ap141031.html

27. IR COBE Milky Way - edge on

28. M100 56 MLY away From a distance, MW might look like this

29. M100 Artist conception of Milky Way http://www.jpl.nasa.gov/news/news.php?release=2010-179

30. 100 000 LY NGC 7331 Spitzer 50 MLY away Blue older stars If this was the MW, where is Earth?

31. 100 000 LY You are here If this was the MW… Downtown Milky Way 30 000 LY

32. Other galaxies Various shapes and sizes Types –Elliptical –Spiral Ordinary spiral (Sa) Barred spiral (Sb) –Irregular –Other Dwarf http://www.astro.cornell.edu/academics/courses/astro201/galaxies/types.htm Large Magellanic Cloud NGC 1365 SB M100 SA M87

33. Other galaxies Most common –Elliptical Oldest –Elliptical Youngest –Irregular http://www.astro.cornell.edu/academics/courses/astro201/galaxies/types.htm Large Magellanic Cloud NGC 1365 SB M100 SA M87

34. Elliptical M87 Virgo 50MLY

35. Ordinary Spiral Galaxies

36. Ordinary Spiral (Sa) Whirlpool Galaxy M51 30 MLY away 60 KLY across

37. Sa M33 Pinwheel or Triangulum Galaxy 3 MLY

38. Sb M31 Andromeda 2.5 MLY 1 trillion stars (3X MW)

39. NGC 4565 30 MLY away 100 000 LY across Needle Galaxy, 240 globular clusters In Coma Berenices (Sb)

40. NGC 613 Sb 65 MLY Sculptor

41. NGC 6946 Sc or Sab 10 MLY away Cepheus

42. Sc M83 15 MLY Hydra

43. Irregular Large Magellanic Cloud – southern hemisphere 180,000 LY away 15,000 LY across

44. Irregular NGC 1569 7 MLY Camelopardalis

45. Galaxies collide

47. Stephen’s Quintet 300 MLY Pegasus

48. 8 BLY

49. NGC 4676 The Mice 300 MLY Coma Berenices

50. Tadpole ARp188 420 MLY Tail is 280 000 LY. Intruder is 300 MLY behind galaxy in front.

51. Antennae galaxies (NGC 4308, 4309) 63 MLY

52. 25 000 ly separation 1200 km/s through gas Image: http://antwrp.gsfc.nasa.gov/apod/ap 060412.html http://antwrp.gsfc.nasa.gov/apod/ap 060412.html Watch Animation (from last lecture): http://chandra.harvard.edu/photo/2006/a40 0/animations.html Binary black holes merging Galaxies merging

53. Andromeda Galaxy has 2 nuclei http://antwrp.gsfc.nasa.gov/apod/ap061126.html

54. 2 nuclei at center of Andromeda galaxy http://antwrp.gsfc.nasa.gov/apod/ap961011.html

55. NASA video of MW and Andromeda Collision http://vimeo.com/43694515

56. The Local Group ~50 members less than 4 million LY away from Milky Way Milky Way, Andromeda Galaxy dominate 2.5 million LY to Andromeda Galaxy

58. Large and Small Magellanic Clouds Southern Hemisphere

59. Triangulum Galaxy

60. Canis Major Dwarf Nearest neighbor

61. Canis Major Dwarf in red Milky Way in blue

62. NGC 6712 Loses Stars into the Milky Way Halo (Artist’s impression) Source: European Southern Observatory ESR PR Photo 06c/99 (18 Feb 1999)

63. Clusters of Galaxies Hercules, 650Mly Credit & Copyright: Jim Misti (Misti Mountain Observatory)Misti Mountain Observatory

64. Seyfert Sextet 190 MLY Serpens each < 35 000 LY

65. Virgo

67. Coma Bernices ~500 MLY Millions of LY to cross

68. Coma 320 MLY http://antwrp.gsfc.nasa.gov/apod/ap070531.html http://antwrp.gsfc.nasa.gov/apod/ap070531.html Sloan + Spitzer (dwarfs, 1000s)

69. Perseus 300 MLY

72. Do clusters cluster? Yes, Superclusters! What is the large scale structure of the universe? What does that tell us about the origin and future of the universe?

73. Stars Binary Stars Open Star Clusters Globular Clusters Milky Way Galaxy Other Galaxies Colliding Galaxies The Local Group Galactic Clusters Next Lecture – Hubble’s Law and Galaxy Motion