Publications by authors named "G Gervino"
Article Synopsis
- The CNO cycle is a key nuclear energy process in stars, particularly significant in hydrostatic hydrogen burning at temperatures between 20 to 80 MK.
- This study reports the first direct measurements of the resonance strength of the ^{17}O(p,γ)^{18}F reaction, revealing a strength about twice as high as previously documented.
- The findings enhance our comprehension of oxygen isotopic ratios observed in red giant stars and in O-rich presolar grains, confirming consistency with earlier results from different reaction channels.
Article Synopsis
- The ^{12}C/^{13}C ratio is crucial for understanding how hydrogen burning occurs in stars and is influenced by specific nuclear reactions.
- Research conducted at LUNA in Italy has measured these reactions at previously unexplored low energy levels, contributing to our understanding of nucleosynthesis in giant stars.
- The team's findings indicate that their reaction rate results are significantly lower than most existing literature, providing a new, more precise estimate for the ^{12}C/^{13}C ratio during hydrogen burning.
One of the main neutron sources for the astrophysical s process is the reaction ^{13}C(α,n)^{16}O, taking place in thermally pulsing asymptotic giant branch stars at temperatures around 90 MK. To model the nucleosynthesis during this process the reaction cross section needs to be known in the 150-230 keV energy window (Gamow peak). At these sub-Coulomb energies, cross section direct measurements are severely affected by the low event rate, making us rely on input from indirect methods and extrapolations from higher-energy direct data.
View Article and Find Full Text PDFLight elements were produced in the first few minutes of the Universe through a sequence of nuclear reactions known as Big Bang nucleosynthesis (BBN). Among the light elements produced during BBN, deuterium is an excellent indicator of cosmological parameters because its abundance is highly sensitive to the primordial baryon density and also depends on the number of neutrino species permeating the early Universe. Although astronomical observations of primordial deuterium abundance have reached percent accuracy, theoretical predictions based on BBN are hampered by large uncertainties on the cross-section of the deuterium burning D(p,γ)He reaction.
View Article and Find Full Text PDFThe ^{22}Ne(p,γ)^{23}Na reaction, part of the neon-sodium cycle of hydrogen burning, may explain the observed anticorrelation between sodium and oxygen abundances in globular cluster stars. Its rate is controlled by a number of low-energy resonances and a slowly varying nonresonant component. Three new resonances at E_{p}=156.
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