  The origin of the elements is a fascinating question that scientists have
been trying to answer for the last seven decades. The formation of light
elements in the primordial universe and heavier elements in astrophysical
sources occurs through nuclear reactions. We can say that nuclear processes are
responsible for the production of energy and synthesis of elements in the
various astrophysical sites. Thus, nuclear reactions have a determining role in
the existence and evolution of several astrophysical environments, from the Sun
to the spectacular explosions of supernovae. Nuclear astrophysics attempts to
address the most basic and important questions of our existence and future.
There are still many issues that are unresolved such as, how stars and our
Galaxy have formed and how they evolve, how and where are the heaviest elements
made, what is the abundance of nuclei in the universe and what is the
nucleosynthesis output of the various production processes and why the amount
of lithium-7 observed is less than predicted. In this paper, we review our
current understanding of the different astrophysical nuclear processes leading
to the formation of chemical elements and pay particular attention to the
formation of heavy elements occurring during high-energy astrophysical events.
Thanks to the recent multi-messenger observation of a binary neutron star
merger, which also confirmed production of heavy elements, explosive scenarios
such as short gamma-ray bursts and the following kilonovae are now strongly
supported as nucleosynthesis sites.
