(stellar) metallicity - The amount of elements heavier than He in stars. Metallicity increases gradually with time because all elements heavier than He are produced by nucleosynthesis in stars. The metallicity of a star (abbreviated Z) can be inferred from its absorption spectrum.
Type I and Type II supernovae - Stars originally more massive than about 9 solar masses end their lives in violent explosions known as a supernova. During a supernova, rapid-neutron addition (r-process nucleosynthesis) can occur, and neutron-rich isotopes (among others) are produced. Type II supernovae are believed to arise from the collapse of stars that have iron-rich cores and hydrogen-rich outer shells. In contrast, type I supernovae are believed to arise from the collapse of white dwarfs that have become overly massive and that have lost their H envelopes. These types of supernovae can be distinguished in spectra by the presence of H in Type II and the absence of H in Type I supernovae.
neutron capture cross-section - This refers to the ability of a particular nuclide to interact with (absorb or capture) free neutrons. It is measured in units of barns (10^-24 cm2). Some nuclides, which have anomalously low neutron cross-sections, have what are known as magic neutron numbers, reflecting an enhanced stability with respect to neutron addition. Stabilities are determined by quantum properties.
spallogenic origin - This refers to the origin of a nuclide by cosmic-ray production.
13C(alpha, n) - This is a short-hand way of writing the reaction: start with a 13C target, add an alpha particle (He nucleus) to it, get a neutron (n particle) out. According to the article, this reaction is believed to be the main source of neutrons in s-process nucleosynthesis (slow-neutron addition) in red-giant stars.
p-process - This is a type of nucleosynthesis characterized
by the addition of protons to nuclides, resulting in proton-rich isotopes.