Astronomers using NASA’s Chandra X-ray Observatory have solved the mystery of AT 2016blu, a massive, unstable star in the spiral galaxy NGC 4559 that repeatedly brightens and dims in optical light, Media Indonesia reported.
The stellar object sits approximately 37 million light-years from Earth. Estimated at 33 times the mass of the Sun, the volatile star earned the moniker supernova impostor
because it periodically flared up without actually destroying itself.
Researchers caught a major optical outburst in March 2026. During this event, the object emitted intense X-rays detected directly by the Chandra telescope.
The data confirmed that a hidden companion—either a black hole or a neutron star—orbits the massive star every 113 days. At the closest point of their orbit, this dense companion strips material away from the unstable star.
For 15 years, the astronomers have been observing this star getting very bright and then dimming regularly,
said Mojgan Aghakhanloo of the University of Virginia in Charlottesville, who led the research.
The stolen material heats up intensely as it falls toward the compact companion, generating the bright X-ray emissions captured by the telescope.
X-ray data combined with optical images from the Sloan Digital Sky Survey revealed the precise mechanics of the system. The 113-day orbit dictates the timing of the outbursts.
When the black hole or neutron star swings close to the massive star, gravitational forces pull stellar gas across the orbital boundary. This accretion process converts gravitational potential energy into thermal and radiative energy.
Scientists have identified an object of this kind with a black hole or a neutron star companion for the first time. NGC 4559 allows scientists to study extreme stellar interactions.
Understanding these binary systems helps astrophysicists map the lifecycle of massive stars. The research clarifies how stellar mass transfer influences the evolution of both components in a binary pair.
- NASA Chandra X-ray Observatory Mission Reports (NGC 4559 Observations)
- Sloan Digital Sky Survey (SDSS) Optical Imaging Database
