Cosmic Cannibalism: Astronomers spot a hungry white dwarf eating its twin star at unmatched pace

Astronomers have discovered a white dwarf star in the binary V Sagittae, some 10,000 light-years away, that is stripping away material at a much higher rate than in any such system known to us hitherto. The finding indicates a stellar interaction of unprecedented force that may ultimately culminate in a stupendous explosive outburst visible to the naked eye.

V Sagittae contains a small white dwarf and a larger, hotter companion star in a tight 12.3-hour orbit. The white dwarf's gravity is stripping away its twin's matter at such a rate that thermonuclear reactions are igniting on its surface. The star cannot absorb all this infalling mass, so it is expelled in excess, creating a bright gaseous halo around both stars. The process has made the entire system much brighter than other such binaries.

When and where did observations occur?

The whole system was first classified in 1902, yet its very bright appearance misled astronomers for over a century. The latest high-resolution X-shooter spectroscopy surveys have produced the sharpest evidence yet of violent behaviour in its mass transfer. The findings emerged in September 2025.