Difference Between Nova and Supernova

Nova vs Supernova

Nova and Supernova are events taking place in our galaxy on a regular basis. These are two concepts that though related with stars, are totally different from each other. However, there are many who believe that supernova is some kind of a bigger, brighter nova, which is totally baseless and wrong.  This article attempts to unravel the mystery surrounding these two astronomical super events that are exciting and interesting for the astronomers.

The confusion between common people pertaining to nova and supernova pertains to sudden brightening of a star (which is called nova), and much more brightening in a star that signals the start of its end (referred to as supernova). Let us first take a closer look around nova. As told earlier, it a sudden brightening phenomenon that takes place in a white dwarf star because of events taking place in a nearby star that forms a binary system with our star (that faces nova). Fusion takes place at the surface of the white dwarf, and the interesting part of the fusion is that it gets initiated with matter that gravitates and accumulates on the surface of the white dwarf from the nearby star. Though, this fusion is not of its own and doesn’t change any physical properties of the star, there is a sudden increase in intensity of light and temperature on the surface of the dwarf star, referred to as nova during this period. This is a process that can take place again and again in the dwarf star, if the binary system continues and fusion material keeps getting accumulated on its surface.

Supernova is the last stage of the life of a star. It is a procedure that destroys the star completely as it is no more able to sustain its gravity. This takes place when the star reaches its critical mass, the definition of which was given by Indian scientist Chandrasekhar, and is thus, called Chandrasekhar limit. When the entire fuel in a star gets burnt up and its existence comes to an end, it becomes very bright, and the process can take months to complete.

There are instances when a supernova takes place in much the same way as a nova with a binary system in place. There is a simple star and a dwarf star just like a nova, but the matter coming from the simple star is much more efficient than in a regular nova. In such a case, fusion that takes place is much more violent and releases many more times energy. This is so high a energy that it ultimately blows off white dwarf star and it becomes a supernova. Even scientists are not sure how this happens and some have proposed a theory of two white dwarfs coalescing.