How is a nova different from a supernova?
The name “nova” means “new” in Latin. In astronomy it’s used to describe an object that suddenly shines much more brightly than it had before. Novae occur in multiple star systems in which a white dwarf, neutron star, or even black hole draws gases from the outer atmosphere of a companion star into an envelope of matter around itself. As more matter is piled on, the gas becomes increasingly hot and dense, until the sudden onset of hydrogen fusion in the envelope triggers an enormous thermonuclear explosion. The star’s brightness increases by one million-fold — enough to make it as luminous as the brightest stars.
