Science: This summer, a dead star in the nearby galaxy Galaxy came back to life in an unusually bright but brief nova, giving astronomers a glimpse of a mysterious class of stellar pair. In May, an array of asteroid-monitoring telescopes on Earth spotted an explosion in the Small Magellanic Cloud (SMC), one of the Milky Way’s closest neighbors, which is home to four of only six known binary star systems consisting of a white dwarf and a hot, young star surrounded by a disk of material. Astronomers expect that such binaries are common throughout the universe, yet only a handful of members have been cataloged so far.
“This is only the second time we have seen such a bright explosion from this type of white dwarf binary system,” Thomas Gaudin, a graduate student at Pennsylvania State University who led the discovery, said in a recent news release. After the initial brightening in the SMC, observations with ground- and space-based telescopes revealed that the explosion was actually from one such rare binary star system, known by astronomers as CXOU J005245.0-722844. Despite being catalogued nearly two decades ago by the Chandra X-ray telescope, little is known about this system.
This white dwarf, once the carcass of a giant star, was enveloped by so much material from its companion star that it exploded like a giant hydrogen bomb. Although the explosion was “extremely luminous,” it lasted for about two weeks, according to a study published last month in the journal Monthly Notices of the Royal Astronomical Society. By June 12, the system fell below the detection limit of the Neil Gehrels Swift Observatory and other telescopes, suggesting that the explosion had ended, the study reports.
