self-propagating star formation
self-propagating star formationA process whereby spiral structure in galaxies is explained by waves of star formation triggered by the explosion of a previous generation of stars as supernovae. Some of the new stars then explode in turn, and thus continue propagating the spiral pattern around the galaxy. P.E. Seiden and H. Gerola calculated in 1979 that the distribution of stars formed by supernova triggering would form spiral arms in a galaxy that was rotating. The theory gives a better fit than the rival density-wave theory to the patchy spiral arms found in many spiral galaxies.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006