Research Division Seminar
Is the riddle of the astronomical Li origin solved?
Lithium is a key element which plays an important role in astronomy as well as everyday human life. Nevertheless it is probably the only element whose astronomical origin is still a mystery. A fraction of about 30% of what is measured today was made in the first 3 minutes of the Universe and about 10% is made by spallation reactions of cosmic rays with the atoms in the interstellar medium. However, as stars burn Li in their hot interiors and what makes the remaining ~60% is still unknown. The recent detections of 7Li and 7Be in the outburst of classical novae is a landmark in the solution of this long standing mystery. The discovery confirms a theoretical speculation made about 50 years ago but which was never supported by observations. Since then the presence of Be-7 has been confirmed to be ubiquitous in about a dozen classical novae and very recently also in the recurrent nova RS Oph that blew out in August 2021. However, the observed values show tension with theory being one order of magnitude greater than predictions. Detailed Li Galactic chemical evolution models assuming the "observed" yields show that indeed Novae could be the long sought source for the Galactic 7Li.
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INAF-Osservatorio Astronomico di Trieste
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