The mysterious blinking of a star that has baffled scientists since it was discovered in 2015 may finally have been explained.
Dimming of Tabby’s Star, known officially as KIC 8462852 but named colloquially for Tabetha Boyajian who first discovered it, has left experts perplexed.
Some have suggested that an ‘alien megastructure’, perhaps a Dyson Sphere used to generate energy, may be responsible for the unusual activity.
Now a new theory has offered a more mundane solution to the puzzle, in the form of a ringed Saturn-like planet.
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The mysterious winking of a star has baffled scientists since it was discovered in 2015. Dimming of Tabby’s Star (artist’s impression) has left experts perplexed but the presence of a ringed Saturn-like planet may provide an explanation
Tabby’s Star, known officially as KIC 8462852 but named for Tabetha Boyajian who first discovered it in 2015, has baffled experts ever since.
Observations revealed its light dimmed regularly, as do distant stars when their planets pass in front of them.
But while the stars of most exoplanet systems are seen to dim by a few per cent, KIC 8462852 dimmed by more than 20 per cent over periods of months.
Some have claimed this dimming could be evidence of a Dyson Sphere – a hypothetical structure which could be used by an advanced alien race to harness the energy of a star.
Scientists remain sceptical, offering that the dimming could be explained by a dust ring around the star or a hail of comets passing in between the star and Earth.
Researchers from the University of Antioquia in Colombia made the claim in a paper published on the Arxiv electronic archive.
They argue that if a ringed planet like Saturn was in close orbit of the star with tilted rings, it would seem to dim the light coming from it in an irregular pattern.
The rings would first block the light as the planet passed in front of the star, followed by the planet itself, before the rings again blocked more light.
And because the tilted rings would be at a different angle on each pass, it would appear to be a random occurrence.
But with enough information, a pattern could be established.
The experts believe Tabby’s Star may have revealed the early years of such a ringed planet, although further research is needed to confirm this.
Writing in the paper, its authors said: ‘In this work we studied a dynamical process, namely the Lidov-Kozai mechanism (LKM), capable of producing a quasi-periodic alteration of the transit’s observable features of a young ringed close-in planet.
‘In the light of our results, it could be possible to speculate about the nature of the hypothetical object orbiting KIC-8462852.
‘Provided enough information one may fit the observable signatures to an oscillating disc of circumplanetary debris subject to LKM.
‘We speculate that if consecutive observations evidence some signatures of a damping in the observed transit depth, we could be witnessing for the first time the disruption of a moon and the birth of a new ringed exoplanet.’
To test their theory the team simulated the light curve, the variation of a star’s visual intensity over time, created by a ringed planet.
They placed this around at a distance from Tabby’s star equivalent to around one-tenth of the distance of the Earth from the sun.
Previous research has suggested a planet five times the size of Jupiter (pictured) could be responsible. A new-found wobble in the rings means that the planet could be the mass of Neptune and still produce the same effect
Experts believe Tabby’s Star may have revealed the early years of such a ringed planet. This graphic shows what happens when a ringed planet passes in front of its host star
They found that at this distance, the star’s gravity would tug on the planet’s rings, making them appear to wobble.
This would make the light distortion effect as viewed form Earth even more irregular.
This is not the first time that a ringed planet has been suggested as an explanation for the star’s behaviour.
In May, Fernando Ballesteros at the University of Valencia in Spain and his colleagues wrote in Arxiv about a gigantic ringed planet with clouds of comets that contain more mass than Jupiter.
The team claimed that a dip in 2011 which reduced the brightness of Tabby’s star by up to 15 per cent, could be explained by a massive ringed planet five times the size of Jupiter transiting in front of it.
The new-found wobble means that the planet could be the mass of Neptune and still produce the same effect.
Astronomers issued an internet-wide ‘call to action’ in May, after discovering that ‘Tabby’s Star’ has once again begun to dim.
The mysterious phenomenon was first detected in 2015, when a star in the constellation Cygnus was found to be ‘winking,’ with dramatic fluctuations in brightness.
Since it was first detected, experts have been hard at work attempting to explain the fluctuations, which have seen brightness dip as much as 20 per cent before reverting to normal.
Some claim this could be evidence of a hypothetical structure which could be used by an advanced alien race to harness the energy of a star.
If an ‘alien megastructure’ really is to blame, one scientist has suggested that spotting it could be relatively easy – as long as experts focus on the right places.
Professor Zaza Osmanov says that astronomers should turn their attention to 64 pulsar stars near our planet, which he believes offer the best chance of hosting an alien megastructure.
In a paper published last year, Professor Osmanov said the alien megastructures are more likely to be shaped like thin discs rather than ‘spherical shells.’
If his theory is correct, this would allow a Dyson’s Sphere to exist in a star’s ‘habitable zone.’
Professor Osmanov argues that if the Dyson’s Sphere does exist in a habitable zone, it should be easy to spot using infrared telescopes.
WHAT IS A DYSON SPHERE?
A suggested method for harnessing the power of an entire star is known as a Dyson sphere.
First proposed by theoretical physicist Freeman Dyson in 1960, this would be a swarm of satellites that surrounds a star.
They could be an enclosed shell, or spacecraft spread out to gather its energy – known as a Dyson swarm.
If such structures do exist, they would emit huge amounts of noticeable infrared radiation back on Earth.
But as of yet, such a structure has not been detected.
Source: All About Space magazine
In a paper published on arXiv, Professor Osmanov said: ‘We have argued that by monitoring the nearby zone of the solar system approximately 64 pulsars are expected to be located inside it.’
But Professor Osmanov has warned that should we find the alien megastructure, it could be extremely powerful.
He said: ‘Rapidly rotating pulsars are very powerful and harvesting their energy would be quite profitable, but a habitable zone would be much farther and mass of a material required for constructing the mega-ring would exceed the total mass of all planets, asteroids, comets, centaurs and interplanetary dust in a typical planetary system by several orders of magnitude.’
This suggests that an alien civilisation living on a megastructure could be strong enough to wipe out humanity.