Blaze Star is set to flare 1,000 times brighter, but its timing remains uncertain

Astronomers and stargazers are watching the night sky for an eruption from a binary star system known as T Coronae Borealis, or the Blaze Star. The system contains two stars: an aging, bloated red giant and a compact, dense white dwarfWhite dwarfThe dense, dead core left behind after a star of low or medium mass exhausts its nuclear fuel. Open in glossary. Roughly every 80 years, the white dwarf pulls matter away from its companion until the buildup triggers a massive thermonuclear explosion.

Why the explosion is hard to time

The last recorded novaNovaA sudden nuclear explosion on a white dwarf star that temporarily makes it shine thousands of times brighter. Open in glossary flare from this system reached Earth in 1946. That timeline means another blast is due. However, researchers cannot pinpoint the exact day or month of the eruption. The date depends on the speed at which hydrogen gas from the red giant collects on the surface of the white dwarf, reaching a critical mass.

Scientists face practical limits when observing the system. The bright glow of the red giant obscures the much dimmer white dwarf. In addition, instruments cannot directly track the precise temperature and pressure of the gas accumulating on the dwarf star. Fluctuations in brightness have already raised expectations, but researchers note that while the blast is very likely to happen before 2030, predicting the moment is similar to forecasting the weather.

What observers will see

Amateur astronomers are monitoring the star system every few minutes. When the runaway reaction begins, the star will surge from magnitude +10 to magnitude +1.7 in less than a day. That jump represents a thousandfold boost in visible light, making it outshine Polaris, the North Star.

The event will be short-lived for casual viewers. The star will remain visible to the unaided eye for only a few days before fading. Binoculars will lose sight of it after about a week. Still, professional telescopes will monitor radiation across radio, X-ray, and gamma-ray wavelengths for months or years after the flare.