Hypernova Nucleosynthesis and Early Chemical Evolution

dc.creatorNomoto, Ken'ichi
dc.creatorMaeda, Keiichi
dc.creatorUmeda, Hideyuki
dc.date2001-10-24
dc.date.accessioned2026-07-07T02:00:59Z
dc.date.available2026-07-07T02:00:59Z
dc.descriptionWe review the characteristics of nucleosynthesis in 'Hypernovae', i.e., supernovae with very large explosion energies ($ \gsim 10^{52} $ ergs). The hypernova yields compared to those of ordinary core-collapse supernovae show the following characteristics: 1) Complete Si-burning takes place in more extended region, so that the mass ratio between the complete and incomplete Si burning regions is generally larger in hypernovae than normal supernovae. As a result, higher energy explosions tend to produce larger [(Zn, Co)/Fe], smaller [(Mn, Cr)/Fe], and larger [Fe/O], which could explain the trend observed in very metal-poor stars. 2) Si-burning takes place in lower density regions, so that the effects of $α$-rich freezeout is enhanced. Thus $^{44}$Ca, $^{48}$Ti, and $^{64}$Zn are produced more abundantly than in normal supernovae. The large [(Ti, Zn)/Fe] ratios observed in very metal-poor stars strongly suggest a significant contribution of hypernovae. 3) Oxygen burning also takes place in more extended regions for the larger explosion energy. Then a larger amount of Si, S, Ar, and Ca ("Si") are synthesized, which makes the "Si"/O ratio larger. The abundance pattern of the starburst galaxy M82 may be attributed to hypernova explosions. Asphericity in the explosions strengthens the nucleosynthesis properties of hypernovae except for "Si"/O. We thus suggest that hypernovae make important contribution to the early Galactic (and cosmic) chemical evolution.
dc.description10 pages. To be published in ``Chemical Enrichment of Intracluster and Intergalactic Medium'' (Vulcano, Italy; May 2001) ASP Conference Series
dc.identifierhttps://arxiv.org/abs/astro-ph/0110528
dc.identifierhttp://arxiv.org/abs/astro-ph/0110528
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/3597
dc.subjectAstrophysics
dc.titleHypernova Nucleosynthesis and Early Chemical Evolution
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