"Star Tabby" continues to delight scientists mysteries

The star KIC 8462852, discovered by astronomer Tabothoy Tabbi, Tabetha Boyajian, attracted the attention of scientists and journalists around the world with unusual changes in brightness, which the biggest enthusiasts attributed to the construction of a Dyson sphere around a star. Several scientific papers one after another refute the assumptions made in previous works. The next work, which refutes the old assumptions and introduces new questions, was published by two teams of astrophysicists .

The star Tabbi is located at a distance of 1480 light years from Earth. It was found as part of a project to search for exoplanets with the Kepler telescope using the transit method. Passing between us and the star, the planets cause a symmetric fall and a subsequent increase in brightness. Last year, astronomers paid attention to this star due to the fact that its brightness fluctuations were uncharacteristic and asymmetric.

The dips in brightness that occurred with a period of 100 days looked like a star obscured by a large swarm of objects of irregular shape. Scientists from Pennsylvania State University even suggested that a Dyson sphere, a mega-object that collects all the energy of a star for further processing, is being built in orbit.
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For the sake of testing this idea, the SETI radio telescopes scanned the star’s surroundings, but found no interesting signals . In addition, such a megastructure was supposed to radiate well in the infrared, which was also not found.

Another team of scientists suggested that an unusually large comet swarm revolves around the star. But astronomer Bradley Schaefer [Bradley Schaefer] from Louisiana State University did not believe in this explanation , and studied the scans of historical photographs of this area of ​​the sky, taken from 1890 to 1989. It turned out that during this time the star's brightness decreased by 20%, and in addition, it calculated that the comet hypothesis does not match the observations.

A serious decrease in the brightness of the star was difficult to explain with anything except the gradual appearance of a megastructure in its orbit. But the use of photographs from the Digital Access to a Sky Century archive prompted a student from Vanderbilt University that the resulting change in the brightness of a star is not due to real processes occurring with the star, but the error in measurements and the use of different telescopes for the archive.

A similar thought occurred to another astronomer working at Lehigh University. Scientists decided to join forces and explore materials from the archive of astrophotography. It turned out that a lot of stars, captured in the photo from the archive, experienced a drop in brightness in the 1960s, which suggests that in fact these changes were caused by the change of equipment used for photographs.

True, even without this, the star raises too many unanswered questions. In 2009, the brightness of the star was observed failure, which lasted a week. It differed from the passage of the planets through the disk of a star in that it was asymmetrical. Then, for two years, the light remained constant, after which a failure of as much as 15% occurred for a week.

In 2013, the light from the star in general began to blink irregularly and according to a complex pattern, and this phenomenon lasted for 100 days. At some moments, the star's brightness dropped by 20%. According to Tabota, for such a darkening would require an object 1000 times larger than the Earth, which would have to pass between us and the star. There are no similar data for any of the stars scanned by Kepler.

None of the hypotheses proposed by scientists (changes in the brightness of the star itself, the collision of planets, clouds of dust, the collapse of a huge comet, the influence of the star’s dwarf companion on its behavior) do not fully fit the observations. It is unambiguously clear that the star is obscuring something - but what, scientists, cannot yet explain.