Related papers: Fine-tuning carbon-based life in the universe by t…
We show that the synthesis of carbon and oxygen through the triple-alpha process in red giant stars is extremely sensitive to the fine details of the nucleon-nucleon (N-N) interaction. A +/-0.5% change in the strength of the N-N force would…
The bulk of the carbon in our universe is produced in the triple-alpha process in helium-burning red giant stars. We calculated the change of the triple-alpha reaction rate in a microscopic 12-nucleon model of the C-12 nucleus and looked…
Through the triple-alpha process practically all of the carbon in our universe is synthesized as the ash of helium burning in red giants. The triple-alpha process proceeds trough the ground state of 8Be and though the 02+-state in 12C. We…
The Hoyle state plays a crucial role in the helium burning of stars that have reached the red giant stage. The close proximity of this state to the triple-alpha threshold is needed for the production of carbon, oxygen, and other elements…
Carbon is produced during the helium burning phase of sufficiently massive stars through the triple alpha process. The $0^+$ energy level of the carbon nucleus allows for resonant nuclear reactions, which act to greatly increase the carbon…
In nucleosynthesis three possible paths are known to bridge the mass gaps at A=5 and A=8. The primary path producing the bulk of the carbon in our Universe proceeds via the triple-alpha process He4(2alpha,gamma)C12. This process takes place…
The astrophysical S--factor and reaction rates for the triple--alpha process are calculated in the direct--capture model. It is shown that the stellar carbon production is extremely sensitive to small variations in the N--N interaction.
The astrophysical S--factor and reaction rates for the triple--alpha process are calculated in the direct--capture model. It is shown that the stellar carbon production is extremely sensitive to small variations in the N--N interaction.
The triple alpha process plays an important role in the production of 12C in stars. Its rate is known with an accuracy of about 12%. We examine the corresponding uncertainties introduced in the description of pre-supernova stars, of…
Motivated by the possible existence of other universes, this paper considers the evolution of massive stars with different values for the fundamental constants. We focus on variations in the triple alpha resonance energy and study its…
The triple-alpha process, whereby evolved stars create carbon and oxygen, is believed to be fine-tuned to a high degree. Such fine-tuning is suggested by the unusually strong temperature dependence of the triple-alpha reaction rate at…
There is an apparent dichotomy between the metal-poor ([Fe/H] <= -2) yet carbon-normal giants and their carbon-rich counterparts. The former undergo significant depletion of carbon on the red giant branch after they have undergone first…
Helium burning is one of the most fundamental steps of stellar nucleosynthesis, as it describes the formation of life-determining element of carbon, while it plays a key role in the evolution of Red Giant, accreting White Dwarfs and Neutron…
Motivated by the possible existence of other universes, with different values for the fundamental constants, this paper considers stellar models in universes where $^8$Be is stable. Many previous authors have noted that stars in our…
We investigate the dependence of the carbon and oxygen production in stars on the 3-alpha rate by varying the energy of the 02+-state of 12C and determine the resulting yields for a selection of low-mass, intermediate-mass, and massive…
Carbon is one of the most abundant metals in the universe because of its synthesis in the fundamental triple alpha reaction. The knowledge of carbon abundances in different environments is one key ingredient to our understanding of stellar…
Nuclear reactions transform atomic nuclei inside stars. This is the process of stellar nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars are reviewed. How stars manage to burn their fuel so slowly most…
Using the standard infall model of Galactic chemical evolution, we explore the origin of carbon and calculate the abundance evolution of CNO elements for 8 different models of stellar nucleosynthesis yields. The results show that, in the…
Effects of a new triple-{\alpha} reaction rate on the s-process during the evolution of a massive star of 25 M\odot are investigated for the first time. Although the s-process in massive stars has been believed to be established with only…
Among stars in Galactic globular clusters the carbon abundance tends to decrease with increasing luminosity on the upper red giant branch, particularly within the lowest metallicity clusters. While such a phenomena is not predicted by…