Stars spend about 90% in their lifetimes fusing hydrogen into helium in significant-temperature-and-tension reactions within their cores. This kind of stars are said to get on the key sequence and are referred to as dwarf stars. The Crab Nebula, stays of a supernova which was first seen around 1050 Advert https://preechaconcretepile82693.bcbloggers.com/35247764/about-star