Astronomers unmask a supernova impostor

Astronomers have unmasked a supernova impostor, a star named AT 2016blu, which was initially thought to be on the verge of exploding as a supernova. The star, located about 29 million light-years away, has shown 27 supernova-like outbursts since its discovery in 2012. The research suggests that these outbursts are not due to an imminent supernova, but rather due to interactions with a previously unseen binary companion. The outbursts are caused by accretion of material from the companion, which heats up and emits X-rays.

• AT 2016blu is a luminous blue variable star, about 33 times as massive as the Sun.
• The outbursts are periodic and occur every ~113 days, likely triggered by periastron passages in an eccentric binary system.
• The study shows that the star's outbursts are not due to a supernova, but rather due to accretion from a compact companion.
• The research indicates that the system consists of a massive star and a compact companion, like a black hole or neutron star, which is accreting material and generating X-rays.

The discovery of AT 2016blu as an accretion-powered outburst challenges previous assumptions about supernova impostors. It is the first known case of an LBV (luminous blue variable) supernova impostor whose outbursts are driven by intermittent accretion onto a compact object. The study highlights the importance of studying such systems to understand the evolution of massive stars and the role they play in the universe.

The research was conducted using multiple telescopes and involved over 30 amateur astronomers. The findings suggest that the star is slowly losing mass to its companion, which is accreting material and producing X-rays. This process causes the star to flare in X-rays each time the orbit allows mass transfer. The study emphasizes that while AT 2016blu is a luminous blue variable, its companion is a compact object, and the outbursts are a result of this interaction. The research also highlights the growing class of models that explain such systems and their role in the universe's evolution.

AI-generated summary of the original article — see the source for the full story.