context: Supernova is a star explosion that can occur in two different ways. A massive star may collapse at the end of the fusion due to its own gravity to a neutron star or black hole, or in a double star a white dwarf may grow its mass beyond the Chandrasekhar border. [1] Supernovs occur every 50 years on average in the Milky Way galaxy. [1] [2] While hundreds of supernovae were previously detected in different galaxies each year, there were 1454 supernovae discovered in 2013, and the number has grown. [3]
question: How does a supernova come about?
answers.text: A massive star may collapse at the end of the fusion due to its own gravity to a neutron star or black hole, or in a double star a white dwarf may grow its mass beyond the Chandrasekhar border