Abstract
In 2011, 100 new nuclides were discovered1. They joined the
approximately 3,000 stable and radioactive nuclides that either
occur naturally on Earth or are synthesized in the laboratory2,3.
Every atomic nucleus, characterized by a specific number of
protons and neutrons, occupies a spot on the chart of nuclides,
which is bounded by ‘drip lines’ indicating the values of neutron
and proton number at which nuclear binding ends. The placement
of the neutron drip line for the heavier elements is based
on theoretical predictions using extreme extrapolations, and so is
uncertain. However, it is not known how uncertain it is or how
many protons and neutrons can be bound in a nucleus. Here we
estimate these limits of the nuclear ‘landscape’ and provide
statistical and systematic uncertainties for our predictions. We
use nuclear density functional theory, several Skyrme interactions
and high-performance computing, and find that the number of
bound nuclides with between 2 and 120 protons is around 7,000.
We find that extrapolations for drip-line positions and selected
nuclear properties, including neutron separation energies relevant
to astrophysical processes, are very consistent between the models
used.