ANANTA Magazine September 2014 | Page 8

There might be an alternative to the silent death of such a star. Most stars exist as companions with same or different lifetimes, orbiting one another. Our sun is a cosmic loner which means it does not have a companion. Other stars, however, face a different predicament when one companion transforms into a white dwarf. As the gravitational pull of the white dwarf is much higher than that of the other star, it begins to parasitically drain the fuel from its companion. The fuel begins to form discs around the dense core until the core destabilizes. A massive explosion follows transforming the star into a “Type 1 Supernova”. Credit : "Progenitor IA supernova" by NASA, ESA and A. Feild (STScI); vectorisation by chris (Wikimedia Commons) Yet some other stars go through a very different cycle. These stars, much more massive than our sun, after depleting their quota of Hydrogen, fuse to form heavier and heavier elements. They go through Carbon, Oxygen, Nitrogen all the way up to Iron! Consequently, the size of the star increases to about 1000 times that of our sun. Once an iron core is formed, fusion is no longer advantageous, since fusion of iron is endothermic and provides the star with no extra energy. The core collapses on itself, giving way to an explosion which is one of nature’s most spectacular fireworks displays, a “Type 2 Supernova”. Only a dead, extremely dense iron core remains.