Once an incredibly massive star reaches the end of its lifetime, it goes out in a blaze of glory that culminates in the star exploding as a supernova. Other than gamma ray bursts, supernovae are the most energetic events we are aware of. In just a fraction of a second, these stars release more energy than our Sun will over the course of its entire lifetime. However, there are various types of stellar explosions, Naturally, some are generated in ways that don't include a core collapse.
Now, astronomers from Georgia State University's 'Center for High Angular Resolution Astronomy' (CHARA) have, for the first time, witnessed the thermonuclear fireball expanding away from a nova in unprecedented resolution. The nova itself, called Nova Delphinus 2013, lurks in the constellation of Delphinus about 14,800 light years from Earth. Found by a Japanese amateur astronomer back in 2013, it was originally believed to be a star.
Now, however, we know that the "star" was actually two stars — a large star with an expansive halo of gaseous material, along with a dense white dwarf (a remnant of a Sun-like star that has passed beyond the main-sequence threshold, into one of the final stages of stellar evolution) — from a binary star system. When two are located in such a close proximity, orbiting a common center of mass, the smaller one tends to siphon material from the larger companion, slowly building up its own hydrogen envelope. Once enough gas has accumulated — by some estimates, 650 feet (200 meters) will do — it ignites a chain reaction within the white dwarf itself