Could Tabby's Star be a planet-eater?

Could Tabby’s Star be a planet-eater?

New hypothesis emerges for the star's strange light signals.

KIC 8462852 – this unassumingly-named star has had a story worthy of a soap opera. Various hypotheses have been put forward to explain the strange fluctuations in its light discovered back in autumn 2015, from orbiting comets to an alien megastructure. But a new study suggests that the star’s light patterns may be explained by a history of gobbling up planets.

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KIC 8462852, also known as Tabby’s Star, is located about 1,480 light-years from us in the constellation Cygnus. Astronomers began to take notice of this star when they spotted sudden dips in its light signal, and then also discovered that the star’s brightness had dimmed by 14 per cent from 1890 to 1989.

Some suggested that these effects could be caused by a vast alien megastructure being built around this star over time, absorbing increasing amounts of energy from the star, and blocking out the starlight as it passed by.

But a new study, published this week in the Monthly Notices of the Royal Astronomical Society, offers a more prosaic suggestion. Astronomers at Columbia University and the University of California, Berkeley suggest that the pattern of light could be explained if the star had eaten up one of more of its planets.

The gravitational energy released as these planetary bodies spiralled into the star would have caused a temporary brightening, from which the star is now recovering – hence the observed dimming. Meanwhile, this cataclysmic event could have created clouds of debris as the planet was torn apart, or had its moons ripped away. This debris would go into orbit, causing the observed dips in starlight as it passed between us and the star.

According to the study’s authors, one strength of this explanation is that it provides a plausible connection between the star’s gradual dimming and its more sudden dips in light. For now, though, their hypothesis remains unproven, so don’t be surprised if there are further twists in the tale…


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