Smash and Grab: A dying stars

June 30, 2019

Dying stars that cast off their outer envelopes to form the beautiful yet enigmatic “planetary nebulae” (PNe) have a new heavy-weight champion, the innocuously named PNe “BMP1613-5406”. Massive stars live fast and die young, exploding as powerful supernovae after only a few million years. However, the vast majority of stars, including our own Sun, have much lower mass and may live for many billions of years before going through a short lived but glorious PNe phase. PNe form when only a tiny fraction of unburnt hydrogen remains in the stellar core. Radiation pressure expels much of this material and the hot stellar core can shine through. This ionizes the previously ejected shroud creating a PNe and providing a visible and valuable fossil record of the stellar mass loss process (PNe have nothing to do with planets but acquired this name because their glowing spheres of ionized gas around their hot central stars resembled planets to early observers).