Gas and Dust Layers from Cas A's Explosive Nucleosynthesis

Lawrence Rudnick

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Our group has developed a new picture of the structure of Cas A's explosion using 5-40 micron images and spectra from the Spitzer Space Telescope. In this picture, two roughly spherical shocks (forward and reverse) were initially set up by the outer layers of the exploding star. Deeper layers were ejected in a highly flattened structure with large protrusions in the plane of the flattening; some of these are visible as jets. As these aspherical deeper layers encounter the reverse shock at different locations, they become visible across the electromagnetic spectrum, with different nucleosynthesis layers visible in different directions. In the infrared, we see the gas lines of Ar, Ne, O, Si, S, and Fe at different locations, along with higher ionization states of the same elements visible in the optical and X-ray parts of the spectrum. These different nucleosynthesis layers appear to have formed characteristic types of dust, the deep layers producing dust rich in silicates, while dust from the upper layers is dominated by Al2O3 and carbon grains. In addition, we see circumstellar dust heated by its encounter with the forward shock. We estimate the total dust mass currently visible that was formed in the explosion to be ∼0.02-0.05 M. Rough extrapolations of these measurements to SNe in high redshift galaxies may be able to account for the lower limit of their observed dust masses. There is a large amount of gas, and presumably dust, that is currently not visible at any wavelength, including both the cooled post-reverse-shock ejecta and the material which has not yet encountered the reverse shock, where some select infrared emission is apparent.

Original languageEnglish (US)
Title of host publicationOrigin of Matter and Evolution of Galaxies - 10th International Symposium on Origin of Matter and Evolution of Galaxies
Subtitle of host publicationFrom the Dawn of Universe to the Formation of Solar System, OMEG 2007
EditorsToshitaka Kajino, Takuma Suda, Takaya Nozawa, Akira Ohnishi, Masayuki Y. Fujimoto, Shigeru Kubono, Kiyoshi Kato
PublisherAmerican Institute of Physics Inc.
Pages353-360
Number of pages8
ISBN (Electronic)9780735405370
DOIs
StatePublished - Jan 1 2008
Event10th International Symposium on Origin of Matter and Evolution of Galaxies: From the Dawn of Universe to the Formation of Solar System, OMEG 2007 - Sapporo, Japan
Duration: Dec 4 2007Dec 7 2007

Publication series

NameAIP Conference Proceedings
Volume1016
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other10th International Symposium on Origin of Matter and Evolution of Galaxies: From the Dawn of Universe to the Formation of Solar System, OMEG 2007
CountryJapan
CitySapporo
Period12/4/0712/7/07

Keywords

  • Dust
  • Explosive nucleosynthesis
  • Infrared emission
  • Supernova remnants

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