ELFT HÍRADÓ

[Szommer Peter <szpl AT metal.elte.hu>]

ELTE Fizikai Intézet

                               ORTVAY KOLLOKVIUM
                                
                    2012. november 8., csütörtök, 15:10-kor
                Az ELTE Pázmány Péter s. 1/A alatti épületében
                           földszinti 0.81 előadóban


              Thomas Rauscher (University of Basel, Switzerland)
                            "The p-Nucleus Puzzle"

Kivonatos ismertetés:

The origin of the intermediate and heavy elements beyond Fe has been a 
long-standing, important question in astronomy and astrophysics. The neutron 
capture s- and r-processes synthesize the bulk of those nuclei. While AGB 
and massive stars were found to contribute to the s-process, the site of 
the r-process still remains unknown. Moreover, a number of naturally occurring,
proton-rich isotopes (the p-nuclei) cannot be made in the s- and r-processes.
Although their natural abundances are tiny compared to isotopes produced in 
neutron-capture nucleosynthesis, their production is even more problematic. 
The long-time favored process, photodisintegration of material in the 
O/Ne-shell of a massive star during its final core-collapse supernova 
explosion, fails to produce the required amounts of p-nuclei in several mass 
ranges. Several alternative sites have been proposed but so far no conclusive 
evidence has been found to favor one or the other. Further important 
uncertainties stem from the reaction rates used in the modeling of the 
thermonuclear burning. This raises the interesting question whether improved 
nuclear physics may (fully or partially) cure the current model deficiences. 
Investigations in astrophysical and nuclear models, together with various 
"observational" information (obtained from stellar spectra, meteoritic 
inclusions, and nuclear experiments) comprise the pieces which have to be 
put together to solve the puzzle of the origin of the p-nuclei. It is an 
excellent example for the multifaceted, interdisciplinary approaches required 
to understand nucleosynthesis.