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Mysterious “blinking star” almost completely darkened for hundreds of days

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A group of astronomers has discovered a gigantic star that has almost completely disappeared from the night sky for hundreds of days, possibly belonging to a new class of “blinking” giant stars. The brightness of the celestial body with the name VVV-WIT-08 fell by up to 97 percent and the researchers have theories about the possible cause, but they cannot fully explain the phenomenon. But they have already found about half a dozen other stars where similar darkening has been observed and they are expecting more discoveries.

Like her now explain in the journal Monthly Notices of the Royal Astronomical Society, they assume that the star giants – about 100 times the size of the sun – are orbited by companions that have not been observed before. This could be a second star or a planet, which in turn is surrounded by an opaque disk. With this they could ensure that the star disappears in the sky and reappears when it slips between it and observer on earth. The scientists now want to research exactly how this darkening takes place and how such systems arise, because the phenomenon cannot yet be fully explained.

VVV-WIT-08 was found by the VISTA Variables in the Via Lactea survey (VVV) of the VISTA telescope at the European Southern Observatory (ESO). This means that around a billion stars are observed over the long term in order to find such fluctuations in brightness. The star VVV-WIT-08 thus discovered does not fit into any known category, explains the University of Cambridgefrom where the analyzes were conducted. It is astonishing that they have found a dark, large and elongated object that must have passed between us and the star, says co-author Sergey Koposov from the University of Edinburgh. One can only speculate what it is, he explains. But there are other stars where something similar has been observed. They could form a common star class.

The discovery mainly evokes memories of the guesswork around the star KIC 8462852, the recurring darkening of which had caused all kinds of speculation. There are various attempts to explain this, but none of them fully satisfy the research community. With VVV-WIT-08, which is located in a comparatively dense region in the center of the Milky Way, the researchers have now also considered whether a dark object could have passed between us and it, far from the star, by chance. However, simulations have shown that in this case there would have to be an incredibly large number of such objects moving through the Milky Way.


(mho)

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