1. Atomic Stellar Nucleosynthesis and Supernova Nucleosynthesis Add + ition Addition

2. Key Atomic Addition – I. Prelude

4. Nuclear Partial Reactions: These surprisingly strange reactions occur commonly as side reactions or as parts of more complex nuclear reactions: 0 n 1 = neutron 1 H 1 = proton -1 e 0 = electron +1 β 0 = positron 0 ν 0 = neutrino 0 γ 0 = gamma rays Atomic Addition – I. Prelude

5. The Three Isotopes of Hydrogen: 1 H 1 = Hydrogen (also symbol for 1 lone proton) 1 H 2 = Deuterium (1 proton and 1 neutron) 1 H 3 = Tritium (1 proton and 2 neutrons)

6. A.Beta Decay – a neutron is converted to a proton by emitting an electron!! 0 n 1 → 1 H 1 + -1 e 0 + 0 ν 0 B.Electron Capture – a proton is converted to a neutron by capturing an electron! 1 H 1 + -1 e 0 → 0 n 1 + 0 ν 0 Atomic Addition – I. Prelude

7. C.Positron Emission – a proton is converted to a neutron by emitting a positron! 1 H 1 → 0 n 1 + +1 β 0 + 0 ν 0 D.Matter/Antimatter Annihilation - a positron and an electron annihilate each other to produce gamma ray energy. +1 β 0 + -1 e 0 → 0 γ 0 Atomic Addition – I. Prelude

8. In the first 10 -4 (0.0001) sec, quarks combined to form protons ( 1 H 1 ) and neutrons ( 0 n 1 ). Over the next minute or so, high energy photons collided to make electrons and neutrinos. II. Big Bang Nucleosynthesis

9. Hydrogen, Helium and a trace of Lithium were the only elements created by the Big Bang. H and He still make up 99.9 % of the universe today: II. Big Bang Nucleosynthesis

10. 1 H 1 + 0 n 1 → 1 H 2 + 0 γ 0 1 H 2 + 1 H 2 → 2 He 3 + 0 n 1 + 0 γ 0 2 H 3 + 1 H 2 → 2 He 4 + 1 H 1 + 0 γ 0 II. Big Bang Nucleosynthesis

11. 1 H 3 + 2 He 4 → 3 Li 7 + 0 γ 0 (Just a trace of 3 Li 7 forms during the Big Bang. (One 3 Li 7 nucleus for every 8 billion 1 He 1 nuclei !) II. Big Bang Nucleosynthesis 3 Li 7 decays with a ½ life of 12 years, so very little remains. 1 H 31 H 3 2 He 4 3 Li 7

12. 4 Be 7 and 4 Be 8 form, but fall apart right away: 2 He 3 + 2 He 4 → 4 Be 7 + 0 γ 0 4 Be 7 + -1 e 0 → 3 Li 7 ( 4 Be 7 turns into 3 Li 7 by electron capture. ) 2 He 4 + 2 He 4 → 4 Be 8 + 0 γ 0 4 Be 8 + 0 γ 0 → 2 He 4 + 2 He 4 4 Be 8 is unstable – it immediately* turns back into 2 2 He 4 ( *after just 10 -17 sec ). II. The “Be Bottleneck”

13. Atomic Addition Hydrogen, Helium and a tiny trace of Lithium were the only elements created by the Big Bang. H and He still make up 99.9 % of the universe today. However, Earth is loaded with heavier elements such as silicon, iron and oxygen. How did all of these larger elements form?

14. Atomic Addition The answer lies at the heart of the Stars :

15. Hydrogen Fusion – 40 Million o C This is the thermonuclear reaction that powers main sequence stars like our Sun.

16. Hydrogen Fusion – 40 Million o C High temperatures & pressures inside a star strip away electrons and overcome the electrostatic repulsion of protons.

17. Hydrogen Fusion – 40 Million o C The strong nuclear force holds protons together once they’re pushed very close together by the high temperatures and pressures:

18. Hydrogen Fusion – 40 Million o C ( +1 β 0 )

19. 1H21H2 Hydrogen Fusion Positron Neutrino Deuteron (“Heavy” Hydrogen) Proton

20. Proton-Proton Fusion Hydrogen fusion powers the Sun and Main Sequence Stars Step 1: Two 1 H  1 2 H

21. Proton-Proton Fusion Step 1: Positron annihilates an electron to make a gamma ray; neutrino flies off.

22. Hydrogen Fusion Deuteron “Light” Helium Gamma Ray Proton

23. Proton-Proton Fusion Hydrogen fusion powers the Sun and Main Sequence Stars Step 2: 2 H + 1 H  3 He Photon of light given off

24. Hydrogen Fusion “Light” Helium Helium Nucleus Proton

25. Proton-Proton Fusion Hydrogen Fusion powers the Sun and Main Sequence Stars Step 3: 2 3 He  4 He + 2 1 H (2 protons fly off to create more fusion reactions.)

26. Proton-Proton Fusion: Power Source of the Main Sequence Stars

27. Carbon-Hydrogen Fusion Nitrogen is produced in the sun by Carbon-Hydrogen Fusion: occurs in small amounts in all stars produces small amounts of Nitrogen and Oxygen: 6 C 12  7 N 13  6 C 13  7 N 14 6 C 12 nucleus fuses with 2 1 H 1 nuclei, giving off a positron ( +1 β 0 ): 6 C 12 + 1 H 1 → 7 N 13 + 0 γ 0 unstable 7 N 13 → 6 C 13 + +1 β 0 + ν 6 C 13 + 1 H 1 → 7 N 14 + 0 γ 0 stable IIIb. Carbon-Hydrogen Fusion

28. Carbon-Hydrogen Fusion Nitrogen is produced in the sun by Carbon-Hydrogen Fusion: occurs in small amounts in all stars produces small amounts of Nitrogen and Oxygen: 7 N 14  8 O 15  7 N 15  8 O 15 7 N 14 nucleus fuses with 2 1 H 1 nuclei, giving off 1 positron ( +1 β 0 ): 7 N 14 + 1 H 1 → 8 O 15 + 0 γ 0 unstable 8 O 15 → 7 N 15 + +1 β 0 + 0 ν 0 7 N 15 + 1 H 1 → 8 O 16 + 0 γ 0 stable IIIb. Carbon-Hydrogen Fusion

29. C-H Fusion only creates a small amount of Carbon, Nitrogen and Oxygen in small-medium Stars like the Sun.

30. Helium Fusion – 200 Million K Red Giant Stage When the sun runs low on Hydrogen in about another 5 billion years, gravity will take over and cause the core to collapse.

31. Helium Fusion – 200 Million K This gravitational compression will cause the sun’s core to heat up to 200 million K and set off a whole new set of nuclear fusion reactions : Helium Fusion.

32. Helium Fusion – 200 Million o C Red Giant Stage

33. Red Giants – Helium forms Carbon

34. Inside a Red Giant 2)Extra heat causes outer shell of hydrogen to fuse into He and billow out into space 1)Helium fuses to form Carbon and Oxygen at the Core

35. Red Giants – Helium forms Carbon

36. …that will engulf Mercury Venus, Earth and Mars and generally “toast” the rest of the solar system!! M V M E J S U V

37. Helium Fusion – Red Giant Core

40. This will be the end of the line for our sun. The core of the red giant is left exposed as it finishes turning the last of its Helium into Carbon. Sirius B White Dwarf Sirius A Large White Main Sequence Helium Fusion Ends – 200 Million K White Dwarf Stage

41. A white dwarf shines because it was a hot star once, but there are no fusion reactions happening any longer. Sirius B White Dwarf Sirius A Large White Main Sequence

42. Helium Fusion Ends – 200 Million K White Dwarf Stage This tiny white-hot ball of Carbon (and a little bit of Oxygen) has collapsed until its electron clouds are pressing against one another. Sirius B White Dwarf Sirius A Large White Main Sequence

43. Helium Fusion Ends – 200 Million K White Dwarf Stage The sun has become a small, white-hot White Dwarf. Sirius B White Dwarf Sirius A Large White Main Sequence

44. Planetary Nebula Helix Nebula “Eye of God” Cats-Eye Nebula Abell 39 Nebula UV Radiation from the exposed White Dwarf core causes the gases of the planetary nebula to fluoresce.

45. White Dwarf to Black Dwarf The white dwarf slowly cools (for billions of years), becoming a Black Dwarf a huge, cool ball of Carbon a big black diamond hanging unnoticed in space.

46. End of the Line for Small Stars Like Our Sun (Black Dwarf) This will be the end of the line for our sun. The carbon core of the black dwarf will collapse and heat up, but it will NOT heat up enough to trigger any new nuclear reactions.

47. End of the Line for Small Stars Like Our Sun – a Ball of Cold Carbon Black Dwarf

48. To review – All stars fuse H into He in their Main Sequence stage. All stars fuse He to make C in their Giant/Supergiant stage. Smaller stars like our Sun stop at this stage. Origin of the Elements Flow Chart

49. Red Supergiants – On Beyond Carbon In larger stars ( > 8.0 M ☉ ), the collapsing Carbon core raises temperature to 600 million K and a whole new round of reactions starts…

50. Origin of the Elements Flow Chart Additional elements fuse with Alpha particles (Helium nuclei) to make larger elements up through Iron (Fe) in the interior of red supergiants by a process called Helium Capture:

51. Red Supergiants – On Beyond Carbon Betelgeuse - a Red Supergiant Orion Rigel – Blue Supergiant Bellatrix – a Blue Giant Betelgeuse’s Future – Supernova!

52. Alpha Process Nucleosynthesis in Supergiants

53. Alpha Process in Supergiants

54. (aka “Helium Capture”)

55. Helium Capture (Alpha Process) in Supergiants One 4 He Nucleus at a time…

56. The End of the Line… Iron ( 56 Fe) is tightly bound and acts like a nuclear “sponge”: it absorbs energy when it tries to fuse to make Zinc-60 ( 60 Zn). When enough Iron accumulates, the star “flames” out for the last time.

57. The End of the Line… So, Fe is the largest element which can be produced inside a star. All elements larger than 56 Fe (and others) are formed during supernovas, when temperatures soar up to 8 billion o C.

58. Neutron Capture in Supernovas – You name it, you got it!! 8 Billion Degree temperatures start a cascade of new elements to form and spread with the explosion.

59. Incredible pressures at the star’s core shove electrons into each nucleus, where they combine with protons by electron capture to make trillions of neutrons: 1 H 1 + -1 e 0 → 0 n 1 + 0 ν e 0 Electron Capture Process

60. The high temperatures and pressures make possible a new “custom designer” process called Neutron Capture. Any number of neutrons can be rapidly added to a nucleus. Neutron Capture Process

61. Neutron Capture can be slow (s process) or it can be rapid (r process): 1) “S” process neutron capture occurs inside late stage red giants - take centuries to complete. The “S” process creates heavy metals such as Gold, Silver, Copper, Lead, Zinc and Zirconium. Neutron Capture Process

62. “S” process neutron capture 26 Fe 56 + 0 n 1 → 26 Fe 57 still stable 26 Fe 57 + 0 n 1 → 26 Fe 58 still stable 26 Fe 58 + 0 n 1 → 26 Fe 59 radioactive (unstable) 26 Fe 59 → 27 Co 59 + -1 e 0 stable Fe decays to Co by Beta ( -1 e 0 ) decay. Neutron Capture “s” Process

63. Beta decay stable unstable stable Beta Decay stable

64. 2)“R” process neutron capture occurs during a supernova - takes place in just a few minutes. So many neutrons are formed that dozens of neutrons may collide and join a nucleus before beta decay can occur. Neutron Capture Process Neutron Proton Electron

65. If you add too many neutrons, the nucleus becomes unstable, so one or more neutrons undergo beta decay to turn into protons to make the nucleus more stable: 0 n 1 → 1 H 1 + -1 e 0 + 0 ν e 0 Neutron Capture Process

66. If one of the neutrons in the nucleus undergoes beta decay into a proton, the nucleus's atomic number increases by one. This continues until a more stable nucleus is achieved. This process repeats over and over again during a supernova to produce the heavy elements found in the universe. Neutron Capture Process

67. This makes it possible to produce an element with any number of protons and neutrons, including rare radioactive elements such as Nobelium (No 250 ), which has a ½-life of 5 millionths of a second (0.000005 sec)! Neutron Capture Process

68. Neutrons are added slowly (one at a time), allowing beta decay to keep up. Neutron Capture “s” Process Neutron capture - stable Neutron capture - unstable Beta decay - stable

69. Neutron Capture “r” Process Key Neutron Capture Beta Decay Any number of neutrons can be rapidly added to a nucleus:

70. Supernova Remnant Cloud Supernova Remnant Clouds are loaded with new, rare exotic heavy elements (Gold, Uranium, etc.)

71. Neutron Capture in Supernovas – You name it, you got it!! Crab Supernova Remnant Cloud (SRC) is loaded with rare, heavy elements.

72. Neutron Capture in Supernovas – You name it, you got it!! SRC from Supernova 1987A

73. Neutron Capture in Supernovas – You name it, you got it!! Evolution of Supernova 1987A and its SRC over the last 14 years

74. Young Supernova Remnant Cloud and Neutron Star

75. Part VII - Spallation by Cosmic Rays: Cosmic rays are primarily protons ( 1 H 1 ) (along with electrons, neutrons and alpha particles) flying through outer space.

76. Part VII - Spallation by Cosmic Rays: Cosmic Rays collide with Carbon (C), Nitrogen (N) and Oxygen (O) atoms in: Meteorites Earth’s atmosphere, or

77. Part VII - Spallation by Cosmic Rays: Cosmic Rays collide with Carbon (C), Nitrogen (N) and Oxygen (O) atoms in: in rocks and soil on Earth’s surface.

78. Part VII - Spallation by Cosmic Rays: These collisions knock protons and neutrons loose from the C, N and O atoms, which then decay to form: Lithium (Li 7 ) Beryllium (Be 9 ) Boron (B 11 ).

79. Part VII - Spallation by Cosmic Rays: For example: Spallation of Carbon by cosmic ray proton to form Boron-11, Boron-10 and Beryllium-9: 6 C 12 + 1 H 1 → 5 B 11 + 2 1 H 1 → 5 B 10 + 2 He 3 → 4 Be 9 + 2 He 3 + 1 H 1

80. Part VII - Spallation by Cosmic Rays: For example: Spallation of Carbon to form Lithium-7 and Lithium-6: 6 C 12 + 1 H 1 → 3 Li 7 + 2 He 4 + 2 1 H 1 → 3 Li 6 + 2 He 4 +2 1 H 1 + 0 n 1 → 3 Li 6 + 2 He 4 + 2 He 3