AAS 201st Meeting, January, 2003
Session 87. Radio and X-Ray SNRs
Poster, Wednesday, January 8, 2003, 9:20am-6:30pm, Exhibit Hall AB

[Previous] | [Session 87] | [Next]

[87.10] Ejecta Knots in Cassiopeia A

U. Hwang (NASA/GSFC, UMD), J. M. Laming (NRL,)

We present initial results from a survey of ejecta knots in Cas A, wherein X-ray data from the Chandra Observatory are used to obtain the temperatures and ionization ages of knots on arcsecond angular scales. These observations are used with models that include an analytical description of the remnant's hydrodynamics and a detailed account of the atomic physics, to constrain the density profiles of the ejecta at localized regions of the remnant. We compare the properties of various knots that are rich in Fe or O/Si. The data favor relatively shallow density profiles for the ejecta. This is consistent with a compact progenitor that underwent substantial mass loss prior to explosion. From the wind parameters in our hydrodynamic models, we are able to estimate the initial stellar mass. To match the observed remnant radius in our models, we also require an initial period of expansion into a tenuous wind that imposes further constraints on the progenitor.

[Previous] | [Session 87] | [Next]

Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.