High-entropy ejecta plumes in Cassiopeia A from neutrino-driven convection.

Recent multi-dimensional simulations suggest that high-entropy buoyant plumes help massive stars to explode. Outwardly protruding iron (Fe)-rich fingers of gas in the galactic supernova remnant Cassiopeia A seem to match this picture. Detecting the signatures of specific elements synthesized in the high-entropy nuclear burning regime (that is, α-rich freeze out) would constitute strong substantiating evidence.

Short-Lived Radioisotope ^{98}Tc Synthesized by the Supernova Neutrino Process.

The isotope ^{98}Tc decays to ^{98}Ru with a half-life of 4.2×10^{6}   yr and could have been present in the early Solar System. In this Letter, we report on the first calculations of the production of ^{98}Tc by neutrino-induced reactions in core-collapse supernovae (the ν process).