Supernova Remnants
The capabilities of Constellation-X will open a new window into the physics of supernova (SN) explosions through a dramatic improvement in the quality of the observations of young, ejecta-dominated supernova remnants (SNRs). The high angular and spectral resolution of Constellation-X will enable determination of the composition, ionization state and velocity of the material throughout the SNR to build a complete model for the structure of the shocked ejecta and the ambient medium.
Constellation-X observations of core-collapse SNRs, will unveil new information about the core-collapse process by revealing the distribution and dynamics of nucleosynthesis products formed during the explo-sion, tracking the early evolution of SNRs, unveiling unshocked iron, and measuring the total mass of iron in SN ejecta. A prime target for studies of core-collapse supernovae is the well-studied Cassiopeia A (Cas A), because it is the brightest X-ray remnant with emission dominated by silicon and iron ejecta. The X-ray emission from Cas A is spatially complex, showing structure on scales from the remnantÕs full ~ 3 arcmin extent to knots and Þlaments <= 2 arcsec in size. Constellation-X will enable deeper investigations into the nature of the knots and other complex ejecta structures as its resolution approaches the goal of 5 arcsec.
Constellation-X will also provide the first sensitive measurements of the odd-z trace elements as well as the trans-iron element zinc in supernova remnants. These elements provide insight into the star that originated the explosion, as well as the origin of these elements. The most abundant species from Ne to S all contain an integral number of alpha particles in their nuclei and are believed to come from carbon and oxygen burning in stellar interiors. The less abundant species (Na, Al, P) come from H-burning beyond the CNO cycle (NeNa, MgAl cycles). The Cr, Mn, and Ni species, in particular, are very important for discriminating among Type Ia SN models. The detection of Zn in a cosmic X-ray source would be a first step towards determining the origin of these elements in a cosmic setting. Again there is no comparable facility that will accomplish these measurements.
