Super-luminous supernovae on the rise

摘要

Although every supernova is remarkably brilliant - at its peak, the average stellar explosion shines about a billion times brighter than the Sun - astronomers have recently discovered an astonishing class of super-luminous supernovae that outshine the ordinary ones by almost a hundredfold. These are very rare examples of extreme stellar death, and their progenitors are unclear, although it has been tempting to associate them with the most massive stars in the Universe. On page 346 of this issue, Nicholl et al. present data that, for certain events, point to a different origin. The origin of ordinary supernovae has been agreed on for decades; the most common events occur when a moderately massive star (one of around 10-20 solar masses) has nearly exhausted its nuclear fuel. The stellar core, now filled with ash, cannot maintain the pressure to withstand its own gravity, and collapses to a dense, compact nugget - a neutron star - releasing enough energy in the process to blow away the outer layers in a supernova explosion.