Introduction to Nuclear Astrophysics I Richard H Cyburt
Introduction to Nuclear Astrophysics I Richard H Cyburt
“We are made of star stuff” Carl Sagan
Nuclear Astrophysics n n Rich & Diverse Interdisciplinary Field Brings together Experimentalists n Observers n Modelers n Theorists n
My Plan n Part 1: Broad Overview n Part 2: Key Concepts & Useful Tools n Helpful Literature n n n n Burbidge, Fowler & Hoyle (B 2 FH) 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 n Study nuclear processes in stars Origin & Evolution of chemical elements n Explosions on/of stars n Dense matter of compact stars n n Determining Important Nuclear Input n Modelers can identify key input Masses n Cross sections/reaction rates n Experimentalists/Theorists produce data n Compare to observations n
What are we made of? See also Asplund, Grevesse & Sauval 2005 and Lodders 2009
Where’s the Nuclear Physics? n Did you notice……. ? Odd-even staggering of abundances? n Larger alpha-nuclei abundance? n Broad peak around Fe 56? n
Average binding energy per nucleon (Me. V) 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/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 n Rapid or r-process n n n Slow or s-process n n n 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, T 1/2 4 Mio years, Merrill 1952)
End of Part I
- Slides: 20
