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Introduction to Nuclear
Astrophysics I
Richard H Cyburt
“We are made of star stuff”
Carl Sagan
Nuclear Astrophysics
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Rich & Diverse Interdisciplinary Field
Brings together
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Experimentalists
Observers
Modelers
Theorists
My Plan
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Part 1: Broad Overview
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Part 2: Key Concepts & Useful Tools
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Helpful Literature
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Burbidge, Burbidge, Fowler & Hoyle (B2FH)
Rev. Mod. Phys. 29 (1957) 547.
Cameron, Pub. Astron. Soc. Pac. 69 (1957) 201.
Cauldrons in the Cosmos, Rolfs & Rodney
Principles of Stellar Evolution & Nucleosynthesis, Clayton
Nucleosynthesis and Chemical Evolution of Galaxies, Pagel
An Introduction to Nuclear Astrophysics, Boyd
Nuclear Physics of Stars, Iliadis
Nuclear Astrophysics includes
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Study nuclear processes in stars
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Origin & Evolution of chemical elements
Explosions on/of stars
Dense matter of compact stars
Determining Important Nuclear Input
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Modelers can identify key input
Masses
 Cross sections/reaction rates
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Experimentalists/Theorists produce data
Compare to observations
What are we made of?
See also Asplund, Grevesse & Sauval 2005 and Lodders 2009
Where’s the Nuclear Physics?
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Did you notice…….?
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Odd-even staggering of abundances?
Larger alpha-nuclei abundance?
Broad peak around Fe56?
Stable Nuclei only!!
For stable nuclei !!!
Nuclide Chart
Some Nucleosynthesis strays from stability….
While others hug the line of stability
Chemical Elements measured by observers
do not oftentimes contain isotopic information
Where the elements are made
Big Bang Nucleosynthesis
BBN predictions
Obs. comparison
Cyburt 2004, 2008
See lectures by T. Kajino & A. Coc for more details
Stellar Evolution
See lectures by O. Straniero for more details
Image from Chandra webpage http://chandra.harvard.edu/edu/formal/stellar_ev/
End Stage of Stellar Evolution
White Dwarf & Type Ia Supernova
Neutron Star & Core Collapse Supernova
See lectures by J. Jose, M. El Eid, W.R. Hix, S. Bishop
Heavy Element Nucleosynthesis
n-capture Processes
Alternating n-capture and beta-decays
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Rapid or r-process
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Slow or s-process
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Time scale ~0.1-1.0 seconds
See lecture by K.L. Kratz
Time scale ~103-104 years
See lecture by M. Busso
Are the abundance patterns universal??
Can decompose pattern…
Can compare w/ observations
r-process enhanced stars
Beers & Christlieb 2005; Frebel & Norris 2011
Where does the s-process happen ?
there !
in red giants – and it takes several million years !
(or, more correctly, low mass TP-AGB stars)
How can we tell ?
Analyze light from a red giant:
Star contains Technetium (Tc) !!!
(heavy element Z=43, T1/2 4 Mio years, Merrill 1952)
End of Part I