2001ApJ...563..185L

Among the many new nuclei synthesized in supernova explosions are unstable proton-rich isotopes. Many of these decay by electron capture, leaving atomic K-shell electron vacancies. The characteristic X-rays emitted when these vacancies are filled can escape the supernova ejecta for sufficiently long-lived isotopes and can possibly be detected by the current generation of X-ray spectrometers. We discuss several candidate isotopes produced in both core-collapse and thermonuclear supernovae. Among the most promising are ⁵⁵Fe, ⁴⁴Ti, ⁵⁹Ni, and ⁵³Mn, which trace various types of explosive silicon burning. These offer the possibility of direct study of individual supernova nucleosynthesis and dynamics, and of the global structure of the Galaxy in multiple stellar populations.