Fallout-Particles from the SN Explosion Seen in Meteorites

Silicon carbide and graphite grains formed 1-10 My after the supernova with properties seen in "fall-out" particles from nuclear explosions. Grains that formed first, grew larger and trapped more radioactive Al-26 (half-life = 740,000 yr) [P. K. Kuroda & W. A. Myers (1996) J. Radioanal. Nucl. Chem., volume 211, pages 539-555]. Pu-244, decaying 100 times slower, was still present when bulk meteorites formed, 100-300 My later.