Infrared Observations of The Helix Planetary Nebula

dc.creatorHora, Joseph L.
dc.creatorLatter, William B.
dc.creatorSmith, Howard A.
dc.creatorMarengo, Massimo
dc.date2006-07-24
dc.date.accessioned2026-07-07T10:39:39Z
dc.date.available2026-07-07T10:39:39Z
dc.descriptionWe have mapped the Helix (NGC 7293) planetary nebula (PN) with the IRAC instrument on the Spitzer Space Telescope. The Helix is one of the closest bright PN, and therefore provides an opportunity to resolve the small-scale structure in the nebula. The emission from this PN in the 5.8 and 8 micron IRAC bands is dominated by the pure rotational lines of molecular hydrogen, with a smaller contribution from forbidden line emission such as [Ar III] in the ionized region. The IRAC images resolve the "cometary knots" which have been previously studied in this PN. The "tails" of the knots and the radial rays extending into the outer regions of the PN are seen in emission in the IRAC bands. IRS spectra on the main ring and the emission in the IRAC bands are consistent with shock-excited H2 models, with a small (~10%) component from photodissociation regions. In the Northeast Arc, the H2 emission is located in a shell outside of the H alpha emission.
dc.description24 pages, 19 figures, accepted for publication in the Astrophysical Journal. A version of the paper with higher resolution images is available at http://cfa-www.harvard.edu/irac/publications/2006refereed/jhora_helix.pdf
dc.identifierhttps://arxiv.org/abs/astro-ph/0607541
dc.identifierhttp://arxiv.org/abs/astro-ph/0607541
dc.identifierAstrophys.J.652:426-441,2006; Erratum-ibid.656:629,2007
dc.identifierdoi:10.1086/507944
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/181102
dc.subjectAstrophysics
dc.titleInfrared Observations of The Helix Planetary Nebula
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