What is the nova and supernova?

Answer 1

• A nova is when a white dwarf or neutron star in a binary system collects enough hydrogen from its partner star, into an atmosphere around itself that is compressed enough to initiate fusion.
• A supernova is when a star dies and collapses into a neutron star or black hole, the collapse is fast enough that to conserve momentum the outer layers of the star are violently blown off in an explosion powerful enough to have the excess energy to produce all the elements past iron well into the transuranics. Supernovas only occur in stars that are very large and very hot to begin with.

Answer 2

A nova is a sudden, short-lived increase in a star's brightness caused by a thermonuclear explosion on the star's surface, often in a binary star system. A supernova is a much more powerful and catastrophic event where a star explodes and releases a huge amount of energy, outshining an entire galaxy for a brief period. Supernovae can result in the creation of elements heavier than iron and can leave behind remnants like neutron stars or black holes.