In About 60 Years, a 'Guest Star' May Shine as One of the Brightest in the Sky

That’s when the two stars in the binary system V Sagittae are set to merge in a spectacularly luminous fashion.
An illustration of a new star in the night sky of 2060, casting its light over a futuristic city.
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Copyright American Institute of Physics

Abigail Malate, Staff Illustrator

(Inside Science) – The constellation Sagitta, or the Arrow, is smaller and less well known than some other ancient constellations. But before the end of this century this humble grouping of stars should point the way toward a spot where a spectacular stellar merger will briefly erupt into one of the brightest objects in the night sky.

Astronomers announced this prediction on Jan. 6 at a meeting of the American Astronomical Society in Hawaii. The expected merger will occur in the binary star system called V Sagittae, which is made up of an ordinary star orbiting a dense white dwarf star. The white dwarf is steadily sucking mass away from its companion.

V Sagittae is currently too dim to see with the naked eye, but by examining old astronomy photos dating as far back as 1890, as well as more recent data, scientists discovered that the system is growing exponentially brighter over time. The increasing brightness is evidence that the ordinary star is spiraling rapidly in toward the white dwarf and losing mass at an increasing rate. 

Projecting ahead in time, astronomers from Louisiana State University in Baton Rouge predict the two stars will merge in spectacular fashion in the year 2083, give or take 16 years, and for about one month, will shine as bright as Sirius, the brightest star in the sky. The last time any “guest star” at least this bright appeared was in 1604, said Bradley Schaefer, a member of the team, in a press release.

Text by: Catherine Meyers, Editor

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Abigail Malate is a graphic designer at the American Institute of Physics, which produces the editorially independent news service Inside Science.