Notes 2

Nuclear Astrophysics is a combination of nuclear physics and astrophysics. Nuclear physics is the study of atomic nuclei, their composition and their interactions, while astrophysics aims at studying galactic objects such as stars and galaxies. Nuclear astrophysics delves into the questions of where and when the elements were created and how nuclear reactions drive cosmic events.

Atomic Nuclei

Atomic nuclei sizes are on the scale of $10^{-14}$ meters and form the (relatively) small centers of atoms while carrying most of the mass. The relevant interactions on that size/mass scale are the electro-weak and strong forces. The basic constituents of atomic nuclei are protons and neutrons which are both spin-1/2 fermions with charge +e and 0, respectively. Protons and neutrons are comprised of three quarks each, fundamental particles on a size scale of $10^{-19}m$.