Artist’s Illustration of Extragalactic Recurrent Nova

This artist's illustration depicts an extragalactic nova eruption. Nova explosions occur in binary star systems in which a white dwarf — the dense remnant of a dead star — continually siphons stellar material from a nearby companion star. As the outer atmosphere of the companion gathers onto the surface of the white dwarf it reaches temperatures hot enough to spark an eruption. Almost all novae discovered to-date have been observed to erupt only once. But a few have been observed to erupt more than once, and are classified as recurrent novae. The span between eruptions for these novae can vary from as little as one year to many decades.

Using the Gemini South telescope, one half of the International Gemini Observatory, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab, and the Carnegie Institution’s Magellan Baade Telescope, a team of astronomers have for the first time observed a recurrent nova outside of the Milky Way in the near-infrared wavelength range. This nova, named LMC 1968-12a, is located in the Large Magellanic Cloud — a satellite galaxy of the Milky Way. It erupts about every four years, which is the third-shortest recurrence timescale of any nova. The team estimates that, during the nova’s early post-explosion phase, the temperature of the expelled gas reached 3 million degrees Celsius (5.4 million degrees Fahrenheit), making it one of the hottest nova ever recorded.