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- Alpha_process abstract "The alpha process, also known as the alpha ladder is one of two classes of nuclear fusion reactions by which stars convert helium into heavier elements, the other being the triple-alpha process. While the triple-alpha process only requires helium, once some carbon is present, other reactions that consume helium are possible:, Q = 7.16 МeV, Q = 4.73 МeV, Q = 9.31 МeV, Q = 9.98 МeV, Q = 6.95 МeV(energy is consumed and the star's core collapses)All these reactions have a very low rate and therefore do not contribute significantly to the energy production in stars;with elements heavier than neon (atomic number > 10) they occur even less easily due to the increasing Coulomb barrier.Alpha process elements (or alpha elements) are so-called since their most abundant isotopes are integer multiples of four, the mass of the helium nucleus (the alpha particle). Alpha elements are Z ≤ 22: (C, N), O, Ne, Mg, Si, S, Ar, Ca, Ti. They are synthesized by alpha-capture prior to the silicon fusing process, a precursor to Type II supernovae. Silicon and calcium are purely alpha process elements. Magnesium can be burned by proton capture reactions. As for oxygen, some authors consider it an alpha element, while others do not. Oxygen is surely an alpha element in low metallicity population II stars. It is produced in Type II supernovae and its enhancement is well correlated with an enhancement of other alpha process elements. Sometimes Carbon and Nitrogen are considered alpha process elements, since they are synthesized in nuclear alpha-capture reactions.The abundance of alpha elements in stars is usually expressed in a logarithmic manner:,Here and are the number of alpha element and Iron nuclei per unit volume. Theoretical galactic evolution models predict that early in the universe there were more alpha elements relative to Iron. Type II supernovae mainly synthesize oxygen and the alpha-elements (Ne, Mg, Si, S, Ar, Ca and Ti) whileType Ia supernovae produce elements of the iron peak (V, Cr, Mn, Fe, Co and Ni).".
- Alpha_process wikiPageExternalLink abstract?identifier=oai:arXiv.org:0705.4511.
- Alpha_process wikiPageID "217607".
- Alpha_process wikiPageRevisionID "594812132".
- Alpha_process hasPhotoCollection Alpha_process.
- Alpha_process subject Category:Nuclear_fusion.
- Alpha_process subject Category:Nucleosynthesis.
- Alpha_process comment "The alpha process, also known as the alpha ladder is one of two classes of nuclear fusion reactions by which stars convert helium into heavier elements, the other being the triple-alpha process.".
- Alpha_process label "Alpha process".
- Alpha_process label "Processo alfa".
- Alpha_process label "Processo alfa".
- Alpha_process label "Réaction alpha".
- Alpha_process label "Альфа-процесс".
- Alpha_process label "عملية ألفا".
- Alpha_process label "アルファ反応".
- Alpha_process label "氦核作用".
- Alpha_process sameAs Réaction_alpha.
- Alpha_process sameAs Processo_alfa.
- Alpha_process sameAs アルファ反応.
- Alpha_process sameAs 알파_반응.
- Alpha_process sameAs Processo_alfa.
- Alpha_process sameAs m.01fw3x.
- Alpha_process sameAs Q1143386.
- Alpha_process sameAs Q1143386.
- Alpha_process wasDerivedFrom Alpha_process?oldid=594812132.
- Alpha_process isPrimaryTopicOf Alpha_process.