Astronomers have seen a "monster" star mysteriously disappear into darkness.
More than 70 million light years away in the constellation of Aquarius, the star is part of the Kinman Dwarf galaxy.
Scientists are not sure why it can no longer be seen but believe there may be two explanations.
The star may have become less luminous, obscured by dust, or may have collapsed into a black hole without exploding as a supernova.
Andrew Allan, a PhD student at Trinity College Dublin, who led the research, said if the star had collapsed and vanished "this would be the first direct detection of such a monster star ending its life in this manner".
He added: "It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion."
Researchers used the European Southern Observatory's Very Large Telescope in the Chilean Atacama Desert to observe the star.
At 75 million light years from us, it is too far for astronomers to see but researchers were able to confirm the star's presence by examining data that revealed its unique chemical signature.
They said that between 2001 and 2011 scientists found evidence of a "luminous blue variable" star 2.5 million times brighter than the sun.
Luminous blue variables are unstable stars prone to giant outbursts.
But by 2019 its telltale signatures could no longer be seen.
Mr Allan said: "We were surprised to find the star had disappeared."
Jose Groh, also of Trinity College and one of the study authors, said: "We may have detected one of the most massive stars of the local universe going gently into the night."
The researchers said further studies were needed to understand what had happened to the star.