A Spectroscopic Study of Nuclear Processing and Production of Anomalously Strong Lines in the Crab Nebula

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dc.creatorMacAlpine, G. M.
dc.creatorEcklund, T. C.
dc.creatorLester, W. R.
dc.creatorVanderveer, S. J.
dc.creatorStrolger, L. G.
dc.date2006-09-28
dc.date.accessioned2026-07-07T11:26:06Z
dc.date.available2026-07-07T11:26:06Z
dc.descriptionWe present and discuss correlations for optical and near-infrared (5500-10030 angstroms) line intensity measurements at many positions in the Crab Nebula. These correlations suggest the existence of gas produced by a range of nuclear processing, from material in which synthesis ended with the CNO-cycle, to some helium-burning and nitrogen depletion, to regions containing enriched products of oxygen-burning. The latter exhibit a gradual, linear rise of [Ni II] emission with increasing argon enrichment, whereas gas with less nuclear processing shows markedly different [Ni II] emission characteristics, including the highest derived abundances. This suggests two origins for stable, neutron-rich nickel in the nebula: a type of "alpha-rich freezeout" in the more highly processed material, and possibly removal of ions from the neutron star in other regions. In addition, the data indicate that anomalously strong observed [C I] emission comes from broad, low-ionization zones. Although the strongest He I emission could also be enhanced in similar low-ionization gas, correlations between relevant line ratios argue against that interpretation, strengthening the case for an exceptionally high helium mass fraction in some locations.
dc.description14 pages, 12 figures, to be published in the Astronomical Journal
dc.identifierhttps://arxiv.org/abs/astro-ph/0609803
dc.identifierhttp://arxiv.org/abs/astro-ph/0609803
dc.identifierAstron.J.133:81-88,2007
dc.identifierdoi:10.1086/509504
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/195720
dc.subjectAstrophysics
dc.titleA Spectroscopic Study of Nuclear Processing and Production of Anomalously Strong Lines in the Crab Nebula
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