Discovery of Outlying, High-Velocity Oxygen-Rich Ejecta in Cassiopeia A

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dc.creatorFesen, R. A.
dc.creatorHammell, M. C.
dc.creatorMorse, J.
dc.creatorChevalier, R. A.
dc.creatorBorkowski, K. J.
dc.creatorDopita, M. A.
dc.creatorGerardy, C. L.
dc.creatorLawrence, S. S.
dc.creatorRaymond, J. C.
dc.creatorBergh, S. van den
dc.date2005-09-03
dc.date.accessioned2026-07-07T10:27:38Z
dc.date.available2026-07-07T10:27:38Z
dc.descriptionHubble Space Telescope images of the young Galactic supernova remnant Cassiopeia A reveal a far larger population of outlying, high-velocity knots of ejecta with a broader range of chemical properties than previously suspected. We identify three main classes of outer ejecta: 1) Knots dominated by [N II] 6548,6583 emission; 2) Knots dominated by oxygen emission lines especially [O II] 7319,7330; and 3) Knots with emission line strengths similar to the [S II] strong FMK ejecta commonly seen in the main emission shell. The discovery of a significant population of O-rich ejecta situated in between the suspected N-rich outer photospheric layer and S-rich FMK-like ejecta suggests that the Cas A progenitor's chemical layers were not completely disrupted by the supernova explosion outside of the remnant's NE and SW high velocity `jet' regions. In addition, we find the majority of O-rich outer ejecta at projected locations out beyond (v = 6500 - 9000 km/s) the remnant's fastest moving Fe-rich X-ray emission material (6000 km/s) seen in Chandra and XMM data along the eastern limb. This suggests that penetration of Fe-rich material up through the S and Si-rich mantle did not extend past the progenitor's N or O-rich outer layers for at least this section of the remnant.
dc.description17 pages including 3 tables and 7 figures. To appear in ApJ
dc.identifierhttps://arxiv.org/abs/astro-ph/0509067
dc.identifierhttp://arxiv.org/abs/astro-ph/0509067
dc.identifierAstrophys.J.636:859-872,2006
dc.identifierdoi:10.1086/498092
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/177203
dc.subjectAstrophysics
dc.titleDiscovery of Outlying, High-Velocity Oxygen-Rich Ejecta in Cassiopeia A
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