A case of astronomical fratricide is doomed to end in a fiery supernova bright enough to be spotted from Earth during the day.

A study published this August in the journal Monthly Notices of the Royal Astronomical Society investigated a binary star system about 10,000 light-years from Earth called V Sagittae. Researchers finally solved the century-long mystery behind what makes it so freaking bright. They found that the system is strangely luminous because one of the pair, a super-dense white dwarf, is absolutely scarfing down on its larger sibling at unprecedented speed.

Eventually, the two stars will collide, producing a supernova explosion of unusual brightness. The event is set to occur “in the coming years,” the researchers said in a university statement.

The brightest of its kind

“V Sagittae is no ordinary star system—it’s the brightest of its kind and has baffled experts since it was first discovered in 1902. Our study shows that this extreme brightness is down to the white dwarf sucking the life out of its companion star, using the accreted matter to turn it into a blazing inferno,” Phil Charles, a co-author of the study and a researcher at the University of Southampton, said in the statement. “It’s a process so intense that it’s going thermonuclear on the white dwarf’s surface, shining like a beacon in the night sky.”

The team observed the extraterrestrial siblings, which orbit each other once every 12.3 hours, using the powerful European Southern Observatory’s Very Large Telescope in Chile. By doing so they also found a giant ring of gas around the binary stars, consisting of the debris from carnage and resulting from the gargantuan levels of energy the white dwarf is generating.

This unexpected finding provides insight that could reshape our knowledge about the birth and death of stars, explained Pasi Hakala, a researcher at the University of Turku and co-lead author of the study. “The white dwarf cannot consume all the mass being transferred from its hot star twin, so it creates this bright cosmic ring,” he continued. “The speed at which this doomed stellar system is lurching wildly, likely due to the extreme brightness, is a frantic sign of its imminent, violent end.”

An even more brilliant end

Pablo Rodríguez-Gil, the other co-lead author and a researcher at the Spanish Instituto de Astrofísica de Canarias and University of La Laguna, says that in the near future, the amassing matter on the white dwarf will probably create a nova outburst. A nova is an explosion in a binary star system, and this one would make V Sagittae visible to people on Earth without the help of any instruments.

“But when the two stars finally smash into each other and explode, this would be a supernova explosion so bright it’ll be visible from Earth even in the daytime,” he concluded.