1. THIS PRESENTAION HAS BEEN RATED BY THE CLASSIFICATION AND RATING ADMINISTRATION TG-13 TEACHERS’ GUIDANCE STRONGLY ADVISED Some Material May Be Unintelligible For Students Under 13. Intense Frames of Scientific Instruction, Analysis, Comparing and Contrasting, Description, and for Some Vocabulary. © 1852 All Rights Reserved VOID WHERE PROHIBITED BY LAW

2. The authorized reproduction or distribution of this copyrighted work is highly encouraged. Lethargic obtuseness is insubordinate and is discouraged by PBIS, as it may result in little or no monetary gain after secondary education or a fine of $250,000. © 1852 All Rights Reserved VOID WHERE PROHIBITED BY LAW PBIS ANTI-VACUITY

3. ASTRONOMY The Milky Way Galaxy

4. OBJECTIVES By the end of this presentation, students will be able to describe the structure of the Milky Way; describe the contents of the Milky Way: multiple star systems. clusters. nebulae.

5. Milky Way Roughly 120,000 ly in diameter; 20,000 ly thick at its core. The sun is located at a distance of about ⅔ the radius from the galactic core on the edge of the “Orion Spiral Arm.”

6. Our Milky Way Galaxy Perseus Arm Orion Arm Sagittarius Arm Centaurus Arm Core

7. Milky Way galactic center

8. Milky Way in Ophiuchus

9. Milky Way Contains an estimated 400,000,000,000 stars. 140 stars per cu. ly. at the core. 0.0026 stars per cu. ly. near the sun. Stars make up an estimated 15% of the galactic mass. 85% of the mass is “unseen material” called dark matter.

10. Milky Way Contains an estimated 400,000,000,000 stars. Roughly 70% are red dwarfs; 9% are white dwarfs; 7.5% are yellow main sequence stars, like our sun. 0.5% are red giants. 0.4% are red supergiants.

11. Milky Way Contains an estimated 400,000,000,000 stars. Roughly 30% are multiple stars Orbits are highly elliptical, non-coplanar, non-concentric, and rather hierarchical. Binary star systems, trinary, and quadruple star systems. Many other stars are bound in clusters.

12. Multiple Star Systems The distance between stars has its limits. Roche Limit – the minimum distance between stars before the tidal forces tear the stars apart. R c = a 3m o ⅓ m p ( )

13. Binary Stars – two stars orbiting each other. Multiple Star Systems No planets can exist within the Roche limit.

14. Multiple Star Systems Trinary Stars – three stars; two orbiting each other; orbiting a third.

15. Multiple Star Systems Quadruple Stars – two stars orbiting each other; orbiting two other stars orbiting each other.

16. Clusters – stars grouped together and bound by gravitational forces Open clusters – moderately close knit, irregularly shaped grouping of stars. Containing 100 to 1000 stars. Subclass of open clusters include Associations and Galactic Clusters.

17. PLieades

18. Clusters – stars grouped together and bound by gravitational forces Globular clusters – massive, tightly packed, symmetrical grouping of stars. Containing 20,000 + stars. May span 16 to 82 ly.

19. Clusters – stars grouped together an bound by gravitational forces Globular clusters – massive, tightly packed, symmetrical grouping of stars. Containing 20,000 + stars. May span 16 – 82 ly. Hercules Cluster In SagittariusIn Ophiuchus Beehive Cluster in Cancer

20. Dark Nebula – cloud rich in dust that happen to be silhouetted against bright background clouds or stars. Diffuse Nebula – gas cloud that looks brighter than the background due to emitted or scattered light. Nebulae

21. Emission Nebula – subclass of diffuse nebulae, near enough to a star, whose heat causes the gas to fluoresce, producing spectral emissions of various colors. Relatively bright and red due to the amounts of H and He present. A blue color indicates the presence of N and/or O. Nebulae

22. Planetary Nebula – subclass of emission nebulae consisting of a hollow shell, bubble, or ring of gas surrounding a hot dwarf star. So named for their spherical shape. Supernova Remnant – subclass of emission nebulae usually curved, wispy segments and much larger than planetary nebulae. Nebulae

23. Helix Nebula

24. Ring Nebula

25. Dumbbell Nebula

26. Crab Nebula

27. Carinae Nebula

29. ANT Nebula

30. Eta Carinae

31. Trifid Nebula

32. Trifid Nebula close up

33. The Horsehead Nebula in Orion

34. Emission Nebula in Ophiuchus

35. Bubble Nebula

36. Rosette Nebula

37. Eagle Nebula

38. Eagle Nebula Close up

39. Veil Nebula

40. N. American Nebula

41. Eskimo Nebula

42. Homunculus nebula

43. Supernova eruption in 1843

44. ASTRONOMY The Milky Way Galaxy