Questions

1. Questions • How do we form hypotheses about the formation of our Solar System? • In what ways can we scientifically test ideas about the Solar System’s formation and early events? • What is the Solar System’s destiny?

2. Building A Solar System

3. Step 1.Fuse Metals

5. Origin of Matter • All matter originated at the Big Bang • Primordial nucleosynthesis • A few minutes after the big bang, protons were highly dense and very energetic, allowing fusion • For about 17 minutes, nucleosynthesis could occur

6. Big Bang Nucleosynthesis • Discussed by Alpher-Bethe-Gamow in 1940s H + H  D • Nearly all deuterium originated in the big bang • Also formed 3He, 4He, 7Li • ~10:1 H:He ratio • Beyond that energy required wasn’t amenable

7. T=1000 s

8. Stars and fusion Lots of fusion http://webhome.idirect.com/~rsnow/aboutstars.htg/H-RDIAGRAM.gif Less fusion

9. Nuclear Fusion • The process of forming a new atomic nucleus by the fusing of two or more nuclei • Hydrogen is “burned” to form Helium, and further fusion leads to other elements • Fusion only occurs at high temperatures (core of the Sun, nuclear bomb, early big bang) Coulombic Barrier + +

10. H  He 2 H D 2 H 4He D + H 3He 2 3He

11. Synthesis of heavier elements • Requires bigger, hotter stars • High temperature means more energy to overcome coulomb barrier • Also means more frequent collisions between nuclei, so short-lived nuclei can act as intermediates

12. More Burning 16O • Triple alpha process 8Be 8Be 2 4He 12C 4He

13. Origin of heavier elements http://www.hacastronomy.com/sn/onion_skin_model.gif

14. From Stellar Nucleosynthesis

15. Heavier elements • Require energy to synthesize • No pay for their own nucleosynthesis • Supernova • Form new elements by proton/neutron capture • Result in the periodic table http://magic.mppmu.mpg.de/snr.jpg

17. Anders and Grevasse 1989

18. Anders and Grevasse 1989 Most abundant elements easiest to synthesize

19. Anders and Grevasse 1989 Heavy elements much rarer than light elements

20. Anders and Grevasse 1989 Sawtooth pattern from addition of He nuclei

21. Anders and Grevasse 1989 Iron peak- the dead end of nucleosynthesis

22. Anders and Grevasse 1989 Easy to burn light elements so Li, Be, B are depleted

23. Step 2.Destroy an old star

24. Supernova 1987a • Brightest Explosion since Kepler’s time • Guess the year it happened! • Ring of expelled gas from earlier • Bipolar filaments

25. Supernova 1987a • Brightest Explosion since Kepler’s time • Guess the year it happened! • Ring of expelled gas from earlier • Bipolar filaments • Hubble has been watching… http://hubblesite.org/newscenter/archive/releases/2004/09/

26. Planetary Nebula • Not actually planetary at all: Herschel thought they looked like planets, that they were new planetary systems forming.

27. Nebula • Orion Nebula • ~2000 Solar Masses

28. Step 3.Condense a New Star

29. Young Stars • Material condenses from “small” shock waves, perturbations in nebula • Spinning increases (Moment of Inertia) • Fusion begins when P/T is achieved • Materials fall into new star and are ejected • This modifies the solar system!

30. Step 4.Get a Proplyd

31. (Pro)to(Pl)anetar(y D)isk = Proplyd • Material spins out like record, Earth • North and South of Sun, material is excavated by jets • Orion Nebula proplyds

32. Step 5.Build Particles

33. Anders and Grevasse 1989 Take a gas of this composition and cool it. What forms?

34. First thing to form: • Ceramics • These are high temperature minerals • First condensates

35. Called Calcium-Aluminum rich inclusions

36. Then come silicates and metal • Olivine and iron

37. Silicates melted • Formed chondrules

38. Volatile materials • Phosphorus • Lower temeprature silicates (Na-, K-bearing) • Sulfides • Ices Where do they go?

39. Step 6.Build Masses

41. Earth formed from Solar System debris • Earth and other planets form from a mixture of rocky material • Meteorites • Asteroids • Comets Hoba- www.nmm.ac.uk

42. Origins of the Earth’s constituents • Volatile components, including key biogenic elements, were in short supply on the early Earth • Earth was hot • Volatiles were lost or were not delivered • Not primordial (20Ne, 36Ar)

43. Loss of volatiles on inner planets P H, C, N, O

44. Delivery of Volatiles to the Earth Cometary Delivery Late Veneer • Carbonaceous Chondrites, with hydrated minerals, were the last accreted constituent to the early earth • Outgassing of volatiles led to hydro + atmosphere • Consistent with D/H ratio • Something odd going on with PGEs • Comets, loaded with H2O and organics, were the source of volatiles • Loaded with water • High flux (possibly) to early Earth • D/H ratio is much higher than earth • What were early comets really like?

45. Step 7.“Crush The Masses” -Stalin

46. Planetary accretion • Dust grains and small particles collide and stick together • Accumulate, making larger and larger bodies • A miracle occurs • Planets form http://ircamera.as.arizona.edu/NatSci102/NatSci102/images/accretion.jpg http://blog.stackoverflow.com/wp-content/uploads/then-a-miracle-occurs-cartoon.png

47. Step 8.Differentiate the Planets

48. Processing of planets • Planets accreted and were warmed • Radioactive decay of short-lived elements? • Impact heating • Warming causes differentiation of planets

50. Step 9.Rearrange and Watch Out