F.-K. Thielemann<br>

Department of Physics and Astronomy, University of Basel,
Klingelbergstrasse 82, CH-4056 Basel, Switzerland<br>

<i>Nuclei far from Stability: Their Role and Production in Astrophysical
Events </i><p>

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Astrophysical explosions can provide thermodynamic conditions which lead
to the production of nuclei far from stability. In combination with the 
environment properties (like the global neutron/proton ratio) this can
favor nuclei near the proton drip-line (the rp-process, rapid proton
capture), moderately proton-rich nuclei (the p- or gamma-process), or very 
neutron-rich nuclei up to the neutron drip-line (the r-process, rapid neutron
capture).<p>

For the astrophysical events involved (e.g. novae, X-ray bursts, supernovae,
neutron star mergers, probably gamma-ray bursts) highly unstable nuclei can
either be of significant importance to explain the explosion energetics
(e.g. in the rp-process in X-ray bursts), or in the other extreme they might
just serve as a means to produce an abundance pattern found in nature
(e.g. in the p- or gamma-process in supernovae).  In case of the r-process
this question can only be answered once its astrophysical site is unambiguously
determined.<p>

In addition, varying amounts of nuclear physics input are needed. In some
cases experimental cross section determinations are required to model an
astrophysical site adequately, in other cases gross properties like masses or
decay half-lives might be sufficient if chemical equilibria are obtained. In
again different cases there is no chance to perform cross section
measurements but nuclear properties can be determined to aid theoretical
cross section predictions.<p>

I intend to provide an overview of the astrophysical sites involved and the
related nuclear physics needs which could be addressed in Rare Isotope
Accelerators.<p>

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