In summary, the measured primordial 7Li abundance falls persistently and significantly below BBN + WMAP predictions, although recently enormous efforts have been spent to experimentally investigate resonances which would amplify 7Be destruction. However, new measurements at higher neutron energy as well as better estimations of the thermonuclear rates of the involved reactions may still be needed in order to solve the long-standing cosmological Li problem.
There are many questions about the role of neutrinos in astrophysics and
cosmology. Cosmic background neutrinos are thought to contribute to dark
matter and may influence large-scale structure formation. In the next
few years, new massive solar neutrino detectors will generate large
amounts of precise data that should have a major impact on our
understanding of how the Sun shines and how neutrinos behave. Among the
most important physics objectives of Super-Kamiokande experiment is to
make a significant contribution toward the understanding of the solar
neutrino physics. The high counting rate of
-e scattering due to
the solar neutrinos and the capability of measuring the recoil-electron
energy spectrum constitute the main points of the Super-Kamiokande
approach to the solar neutrino puzzle. It will be important to observe
the abundant low-energy solar neutrinos in order to test more precisely
the theory of stellar evolution. Solar neutrino experiments at low
energies can provide refined measurements of the parameters that
describe neutrino oscillations. A broad range of neutrino detectors with
low thresholds is required to make the necessary
measurements. Furthermore, future recordings, tests, and data taken over
a longer period of time will allow us to probe important aspects of
neutrino physics.
The production of heavy elements in ccSNe is dominantly related to the
neutrino-driven wind phase, in which matter is ejected from the
proto-neutron star due to neutrino-nucleon interactions. Astrophysical
parameters in the neutrino-driven wind, such as entropy and electron
fraction, will determine which nucleosynthesis process occurs. The
studies for the
-nucleosynthesis in the outer
shells of the star during ccSNe need better observational constraints in
order to be confirmed. It would be interesting in the future to study
the
-nucleosynthesis in more
detail within a full detailed hydrodynamical simulation of the explosion
of the star. When this star has an s-process contribution, it would be
significant to study the influence of
-nucleosynthesis on the
complete set of s-process elements, and not only for a small subset of
all nuclei as it has been done in previous work. Regarding r-process,
coalescence of NS binaries is one of the most plausible sites for
nucleosynthesis and they have been extensively studied. In NS mergers,
the r-process material originates in the NS crust, and the composition
of the crust and how it responds to stress caused by the merger dictates
the amount of r-process material which is ejected. In the near future,
the target will be to build a consistent picture of NSs and the nuclear
physics that governs them, informed by gravitational waves, X-ray
observations and laboratory experiments.
Further research on GRBs may help scientists to understand the history of element production in the Milky Way by providing a record of events. Short GRBs are expected to create significant quantities of neutron-rich radioactive species - gold, uranium, plutonium - whose decay should result in a faint transient in the days following the burst, the so-called kilonova. The new generation of gravitational wave detectors (Advanced-LIGO and Advanced-VIRGO) has already reached sufficient sensitivity levels to detect NS and NS-BH mergers out to distances of a few hundred Mpc. The recent simultaneous detection of the electromagnetic counterpart with gravitational waves has officially begun the era of multi-messenger astronomy and has confirmed short GRBs as sites of heavy elements production. Studying the universe with these two fundamentally different types of information will offer the possibility of a richer understanding of the astrophysical scenarios as well as of nuclear processes and nucleosynthesis.
Acknowledgments This work is a part of the project INCT-FNA Proc. No. 464898/2014-5. The authors would like to acknowledge FAPESP for financial support under the thematic Projects 13/26258-4, 2016/17612-7 and 2017/05660-0 and through the regular research support process 2013/17696-8. Support from the CNPq is also acknowledged.
VL received support from CAPES through the “Science Without Borders” project, and MSH acknowledges a Senior Visiting Professorship granted by CAPES/ITA.
Finally, the authors would like to thank the referee for the careful reading of the manuscript and valuable comments that contributed to the improvement of the paper.