The secret of the star Tabbi: no aliens, sorry

The strangest and perhaps the most mysterious star in the known universe has many names, but it is very likely that soon it will lose the most "unscientific" of them. The KIC 8462852, the same star of Tabbi, who is also a "star with an alien megastructure", became one of the most hotly debated in the past year 2017. However, the results of the new study, initiated by Tabeta Boyajyan herself, an astronomer who first noticed the unusual behavior of the star back in 2015, say that speech is definitely not about some alien megastructure.

In fact, the star KIC 8462852 was first observed by astronomers of the 19th century and appeared many times in various astronomical studies after that. However, the highlight of her speech was in 2015, when Boyadjian and her fellow researchers reported very strange indicators of the detected data collected by the space observatory Kepler.

All the stars are flickering. Observation of this phenomenon from the Earth can be explained by the peculiarity of the interaction of starlight with the atmosphere of our planet. In space, this phenomenon can be immediately due to a number of factors. For example, one of such factors is the transit of planets passing between their native stars and the field of our observation. As a result, we can observe a short-term decrease in brightness, which, as a rule, has not very high values ​​- something about 1 percent. By the way, thanks to this transit, astronomers usually look for new exoplanets.

But with the star KIC 8462852 everything turned out quite differently. The team of Tabate Boyajyan found that changes in the brightness of the star, which is about 1280 light years away from us, are not just significant – they are huge. Astronomers have witnessed a decrease in the brightness of the star up to 22 percent, and finding an appropriate explanation for this phenomenon proved to be extremely difficult. For this, none of the factors known to us simply did not fit. At least for now.

We could all write off on the transit of some planet circling around the star, but the periodicity of the brightness variation of KIC 8462852 was unstable, which actually put an end to this assumption.

Another supposed explanation was the participation of a certain swarm of comets and other interstellar garbage. Some scientists have advanced the theory that the peculiarity of such a strange behavior of a star can be related to its own internal processes occurring inside KIC 8462852 – supposedly it is in a kind of transition period. Another hypothesis was that the star could devour the planet, and a decrease in brightness could cause the debris of this planet.

In the end, a very futuristic hypothesis was put forward – for all of this observed "magic" there can be an alien extraterrestrial megastructure surrounding the star. Allegedly, the aliens have built around the star a kind of Dyson sphere that collects the energy of the light and at the expense of its size blocks from us a huge volume of light from time to time KIC 8462852.

While other astronomers were trying to find a reasonable explanation for the observed anomalies, the Boyadjian team conducted a successful fund-raising campaign at the Kickstarter site and leased an observatory for a more detailed study of the KIC 8462852 star when it again reduced its brightness. The results of the work were shared by the scientists in The Astrophysical Journal Letters.

"We hoped that if we saw the flicker in real time, we could figure out the depth of it on all wave bands," says one member of the team of astronomers, Jason Wright of the University of Pennsylvania (USA).

"If the depth of these scintillations turned out to be almost the same, it would say that the reason for the dimming is something opaque, a disc, perhaps a planet or a star, or maybe even something more large in space. "

But astronomers, like the proponents of the hypothesis of an alien megastructure, were disappointed.

Four episodes of dimming were observed by researchers at the Las Cumbres Observatory in California (USA) between March 2016 and December 2017. Multispectral light analysis of KIC 8462852 showed that brightness in some wave bands decreases more than in others.

"New data show that different light waves are blocked with different intensities. Therefore, whatever happens at this moment between us and the star – it does not have a full opacity, as one would expect from a planet or some kind of extraterrestrial megastructure, "says Boyajyan.

Despite the fact that perhaps the most desired explanation for the unusual behavior of the star KIC 8462852 after such conclusions will have to be deleted, we still do not have an answer to the question of what exactly causes such an unusual change in the luminosity of this star. Yes, the alien mega structure is hardly a cause, but something like this should explain such a significant decrease in brightness? It could be dust, comets, some kind of interstellar garbage. From this, the mystery of the star Tabby does not become less interesting. No, of course, it becomes, but scientists still really want to find the true reason for the abnormal behavior. Especially when a lot of time, money and nerve cells were already spent on it.

"The last study crosses out the option with the alien megastructure, but at the same time leaves a lot of questions and possibilities for the presence of other phenomena that could be behind this decrease in the luminosity of the star," explains Wright.


What exactly are the phenomena – scientists do not yet have an unambiguous answer, but they are going to continue their work until they find the right solution.

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