Rare Isotopes: The DNA of Stellar Explosions

Transcription

1 Rare Isotopes: The DNA of Stellar Explosions Chris Wrede Michigan State University National Superconducting Cyclotron Laboratory PHY492/802 substitute lecture April 21 st, 2017

2 Outline Introduction: How were the chemical elements made? Example: How is aluminum-26 produced in the Milky Way? Future: The Facility for Rare Isotope Beams (FRIB) C. Wrede - Slide 2

3 Big Bang nucleosynthesis Big Bang made 75% H and 25% He, by mass The Essential Cosmic Perspective, Bennett, Donahue, Schneider, Voit, 7 th Ed. C. Wrede - Slide 3

4 How were other elements made? C. Wrede - Slide 4

5 In stars and exploding stars! C. Wrede - Slide 5

6 Life of a low-mass star (less than about 8 solar masses) Protostar forms in molecular cloud Red giant burns He into C, O, Ne White dwarf remnant Star burns H into He Planetary nebula The Essential Cosmic Perspective, Bennett, Donahue, Schneider, Voit, 7 th Ed. C. Wrede - Slide 6

7 Life of a massive star (more than about 8 solar masses) Protostar forms in molecular cloud Supergiant burns He into C, O,, Fe Neutron star or black hole remnant Star burns H into He Core-collapse supernova The Essential Cosmic Perspective, Bennett, Donahue, Schneider, Voit, 7 th Ed. C. Wrede - Slide 7

8 Binary star systems Neutron-star mergers, thermonuclear supernovae, classical novae, Credit: Daniel Price (U/Exeter) and Stephan Rosswog (Int. U/Bremen) C. Wrede - Slide 8

9 The Milky Way: a cosmic recycling plant New stars & planets form in cold molecular clouds Stars expel new elements Stars create new elements The Essential Cosmic Perspective, Bennett, Donahue, Schneider, Voit, 7 th Ed. C. Wrede - Slide 9

10 Example: radioactive 26 Al across Milky Way 2-3 solar masses observed Half life of 700,000 years Direct evidence for ongoing stellar nucleosynthesis in Milky Way Data from COMPTEL & INTEGRAL-SPI Figure courtesy of MPE Garching / Roland Diehl C. Wrede - Slide 10

11 26 Al and water on Earth Injection of 26 Al into the molecular cloud that collapsed to form our Solar System affected the amount of water we have on Earth today vs. vs. Lots of 26 Al Just enough 26 Al H. C. Urey, Proc. Natl. Acad. Sci. U.S.A. 41, 127 (1955) G. Srinivasan et al., Science 284, 1348 (1999) F. X. Timmes, Nuclear Astrophysics Town Meeting (2012) Not much 26 Al C. Wrede - Slide 11

12 26 Al and supernova models Massive stars and their core-collapse supernovae are a substantial source of 26 Al but are difficult to model. Instead, try to determine how much 26 Al is from other sources and use 26 Al/ 60 Fe ratio as a model constraint. Figure courtesy of MPE Garching / Roland Diehl C. Wrede - Slide 12

13 Potential 26 Al source: classical novae Nova Cygni 1992 (in 1994) NASA, ESA, HST A nova is a thermonuclear explosions on the surface of a white dwarf star accreting hydrogen from a binary companion David A. Hardy/ S. Starrfield et al., (1971, 1972) J. Jose et al., Nucl. Phys A777, 550 (2006) C. Wrede - Slide 13

14 Nucleosynthesis in novae Z = number of protons in nucleus N = number of neutrons in nucleus Stable isotope Rare isotope 26 Al J. Jose, Proceedings of Science, NIC XI 050 (2011) C. Wrede - Slide 14

15 25 Al + p 26 Si + g reaction in novae Just need to measure one more nuclear reaction! C. Wrede - Slide 15

16 Determining 25 Al + p 26 Si + g reaction rate using 26 P b decay Reaction rate depends on the properties of one special excited state in the 26 Si nucleus We can study this state using the b decay of 26 P Looking for a g ray with an energy of 1.74 MeV C. Wrede, Phys Rev. C 79, (2009) C. Wrede - Slide 16

17 Determining 25 Al + p 26 Si + g reaction rate using 26 P b decay Reaction rate depends on the properties of one special excited state in the 26 Si nucleus We can study this state using the b decay of 26 P Looking for a g ray with an energy of 1.74 MeV C. Wrede, Phys Rev. C 79, (2009) C. Wrede - Slide 17

18 National Superconducting Cyclotron Lab (NSCL) National user facility for rare isotope science and education: Nuclear structure, nuclear astrophysics, fundamental symmetries, societal applications On Michigan State University campus in East Lansing, MI C. Wrede - Slide 18

19 Production of rare isotope 26 P at NSCL 5.4 GeV 36 Ar beam, Be target 75% pure beam of up to P ions per second at experiment M. B. Bennett et al., Phys. Rev. Lett. 111, (2013) NSCL Experiment 10034, C. Wrede spokesperson C. Wrede - Slide 19

20 Segmented Germanium Array (SeGA) Used to detect g rays following 26 P b decay M. B. Bennett et al., Phys. Rev. Lett. 111, (2013) NSCL Experiment 10034, C. Wrede spokesperson C. Wrede - Slide 20

21 Spectrum of 26 Si g rays following 26 P b decay Small 1.74 MeV peak, so reaction rate slow in a nova: nuclear physics done! M. B. Bennett et al., Phys. Rev. Lett. 111, (2013) NSCL Experiment 10034, C. Wrede spokesperson C. Wrede - Slide 21

22 Nuclear result + astrophysical simulation + Milky Way nova rate Amount of 26 Al produced in novae on white dwarfs of different masses: Conclusion: novae produce up to 30% of the 26 Al in Milky Way M. B. Bennett et al., Phys. Rev. Lett. 111, (2013) NSCL Experiment 10034, C. Wrede spokesperson Astrophysical simulations by Jordi Jose (UPC Barcelona) C. Wrede - Slide 22

23 Future: Facility for Rare Isotope Beams (FRIB) C. Wrede - Slide 23

24 Scientific Reach of FRIB Rare Isotope Beam Rates FRIB will deliver 1000x the rare isotope quantities as NSCL O. Tarasov - groups.nscl.msu.edu/frib/rates/ C. Wrede - Slide 24

25 Facility for Rare Isotope Beams (FRIB) Experimental Systems Ion Source Linac Support FRIB construction site on February 13, Web cameras at Front-end building turned over with conventional utilities operational in December 2016 Civil construction substantially complete in March 2017 C. Wrede - Slide 25

26 FRIB Technical Construction Progress Linac tunnel view, looking East C. Wrede - Slide 26

27 Summary Rare isotopes are like the DNA of exploding stars FRIB will provide rare isotopes whose properties determine how exploding stars synthesize the chemical elements C. Wrede - Slide 27

28 Thank you for your attention! C. Wrede - Slide 28

29 NSCL Experiment collaboration Classical-Nova Contribution to the Milky Way s 26 Al Abundance: Exit Channel of the Key 25 Al(p,g) 26 Si Resonance Phys. Rev. Lett. 111, (2013) M. B. Bennett, 1,2,* C. Wrede, 1,2,3, K. A. Chipps, 4 J. Jose, 5 S. N. Liddick, 6,2 M. Santia, 1,2 A. Bowe, 1,2,7 A. A. Chen, 8 N. Cooper, 9 D. Irvine, 8 E. McNeice, 8 F. Montes, 2,10 F. Naqvi, 9 R. Ortez, 1,2,3 S. D. Pain, 11 J. Pereira, 2,10 C. Prokop, 6,2 J. Quaglia, 12,10,2 S. J. Quinn, 1,2,10 S. B. Schwartz, 1,2,13 S. Shanab, 1,2 A. Simon, 2,10 A. Spyrou, 1,2,10 and E. Thiagalingam 8 1 Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA 2 National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA 3 Department of Physics, University of Washington, Seattle, Washington 98195, USA 4 Department of Physics, Colorado School of Mines, Golden, Colorado 08401, USA 5 Departament Fisica i Enginyeria Nuclear (UPC) and Institut d Estudis Espacials de Catalunya (IEEC), E Barcelona, Spain 6 Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA 7 Physics Department, Kalamazoo College, Kalamazoo, Michigan 49006, USA 8 Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada 9 Department of Physics and Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520, USA 10 Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA 11 Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 12 Department of Electrical Engineering, Michigan State University, East Lansing, Michigan 48824, USA 13 Geology and Physics Department, University of Southern Indiana, Evansville, Indiana 47712, USA Spokesperson: wrede@nscl.msu.edu C. Wrede - Slide 29

30 Facility for Rare Isotope Beams FRIB will be a $730 million national user facility funded by the Department of Energy Office of Science (DOE-SC), Michigan State University, and the State of Michigan FRIB Project completion date is June 2022, managing to an early completion in fiscal year 2021 FRIB will serve as a DOE-SC national user facility for world-class rare isotope research supporting the mission of the Office of Nuclear Physics in DOE-SC FRIB will enable scientists to make discoveries about the properties of these rare isotopes in order to better understand the physics of nuclei, nuclear astrophysics, fundamental interactions, and applications for society C. Wrede - Slide 30