(ORDO NEWS) — Using the Very Large Telescope (VLT) of the European Southern Observatory, astronomers observed the disappearance of an unstable massive star located in a dwarf galaxy. Scientists believe that the explanation for this fact may consist in the fact that at first there was a decrease in the brightness of the star, and then – its light was blocked by dust. An alternative explanation is that the star collapsed into a black hole without a supernova flash. “If that is confirmed,” says Andrew Allan, research team leader and graduate student at Trinity College Dublin, Ireland. “That will be the first case of the discovery of such a“ silent death ”of a giant star.”
Between 2001 and 2011 several different groups of astronomers have studied this mysterious massive star, belonging to the class of bright blue variable stars and located in the Kinman dwarf galaxy, and these observations indicated that the star is at a late stage of evolution. Allan and his colleagues intended to conduct new observations of this star and directed the VLT telescope to the distant dwarf galaxy Keenman in 2019, but did not find any signs of the presence of the star in its former place. “The star just disappeared!” – said Allan.
Located at a distance of about 75 million light-years from us in the direction of the constellation Aquarius, the Kinman galaxy is too far from the Earth to be able to distinguish individual stars, but astronomers have the opportunity to observe signs of the presence of stars of certain classes in the galaxy. Bright blue variable stars, in particular, show characteristic sharp jumps in brightness – however, observations made in 2019 did not reveal such jumps from the Kinman galaxy, Allan explained.
To explain this mysterious “disappearance” without an accompanying supernova explosion, Allan’s team offers two versions. According to the first version, at first there could be a decrease in the brightness of the star, and then a faded star could hide behind a cloud of dust. An alternative explanation is the transformation of a star into a black hole without a characteristic flash of light – however, in this case, astronomers would witness a very rare event, since usually massive stars flare up as supernovae at the end of their life cycles.
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