For decades, observing stars and compiling star catalogs, scientists notice objects that suddenly disappear. The phenomenon has given rise to many hypotheses, from extreme types of stellar death and completely new astrophysics to alien technology.
A team of researchers from the project "Disappearing and Emerging Sources over a Century of Observations" has checked whether all these stars really disappear without a trace.
“Finding a disappeared star - or a star that came out of nowhere - would be a tremendous discovery and would undoubtedly mean a new astrophysics,” says Beatrice Villarroel, a theoretical physicist at Stockholm University.
Scientists have compared 600 million stars in the USNO catalog with the collection created by the University of Hawaii's Pan-STARR system. Data from these catalogs have been collected for about 50 years.
First, they found about 151,000 candidates for "disappeared stars". Then this number was narrowed down to 23.7 thousand. It turned out that many simply moved farther than expected.
The team removed images with imperfections that could not be definitively determined, and weeded out stars around the edges of images that could be noise in the image.
Finally, the researchers left only about 100 truly "disappeared" stars, which could not be tracked in any of the catalogs.
There are several explanations for their disappearance. According to the first, some objects in space sometimes flare up brightly enough to be noticed, but then decrease brightness again by several magnitudes. The second hypothesis is that these are just "scratches" or noise in the pictures. Or, these stars could have moved very far away and ceased to be visible to telescopes.
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All these versions will need to be checked before declaring the discovery of new unusual stars, astrophysicists summed up.
Anna Lysenko