The European Southern Observatory captures the disappearance of a star


It is the first direct detection of a massive star in a dwarf galaxy that disappears without producing a supernova

The “mysterious” star disappearance


Between 2001 and 2011 various groups of astronomers had studied this mysterious massive star, located in the dwarf galaxy Kinman, indicating that it was in an advanced evolutionary phase. The group led by Andrew Allan of Trinity College Dublin – with collaborators in Ireland, Chile and the United States of America – wanted to find out more about where the life of the massive stars ends and the object in the dwarf galaxy Kinman seemed the perfect target . But when they pointed ESO’s VLT to the distant galaxy in 2019, they could no longer find indications of the star’s presence.

There are two hypotheses put forward by scientists. The star may have become less bright and partially obscured by dust. Or it could have collapsed to form a black hole without producing a supernova. “If it were true – says Andrew Allan – it would be the first direct identification of a gigantic star that ends its life”.

The history of observing the celestial body

Located about 75 million light years away from us in the Aquarius constellation, the dwarf galaxy Kinman is too far away for astronomers to see its individual stars, but they can detect clues to the presence of some of them. From 2001 to 2011, the light received from the galaxy continued to show the presence of a “bright blue variable” star approximately 2.5 million times brighter than the Sun. These stars are unstable, but still leave specific traces. that scientists can identify. These were absent from the data collected by the team in 2019 – with four 8-meter telescopes of the VLT – and thus the first doubts arose about the end of the same. To confirm the disappearance the new observations with the X-shooter tool installed on ESO’s VLT, without finding any trace.

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