Guardian: For the first time, astronomers have captured images of a nova, a nuclear explosion on a white dwarf star. Nova Delphini 2013 was first detected last year by the CHARA Array IR telescope at Mount Wilson Observatory in Los Angeles. Such explosions are believed to occur in binary star systems, when a white dwarf is able to accrete enough hydrogen from its companion star that it ignites and starts nuclear fusion. Within hours of the explosion, astronomers were able to point the array telescopes toward the nova to take interferometric measurements of its size and expansion rate. From that data, they have determined that the nova is about 14 800 light-years from the Sun, which means the explosion occurred some 15 000 years ago. When last measured 43 days after the explosion, the nova had expanded nearly 20-fold.
