In a relatively distant place, approximately 1,480 light years away from Earth, sits one of the most controversial objects in our galaxy, KIC 8462852, as its dubbed, clearly becomes the primary subject of much ongoing research.
The star KIC 8462852 is apparently a completely-ordinary main sequence star, much like our sun, with no spectral peculiarities and no emission lines or anything unusual; Its located in the constellation Cygnus, appearing in the original field studied with the NASA’ Kepler spacecraft.
But this star catch our attention being in the news recently for unexplained and strange behavior, too odd even by the generous standards of cosmic phenomena.
The Planet Hunters project discovered in the Kepler light curve that KIC 8462852 displays a unique series of aperiodic dips in brightness, the star faded by 0.2%–20% with duration from a day to weeks — such fast variations of a single main sequence star are inexplicable.
In September 2015 astronomers and citizen scientists associated with the project uploaded a paper on arXiv describing the data and possible interpretations of KIC 8462852 behavior.
Since the paper was published, scientists have been speculating on what could be causing such irregular dips. Yale University researcher Tabetha Boyajian, who first spotted KIC 8462852 signals, published a study which describes various scenarios to explain the dipping events observed in the Kepler light curve. But lately, most of the proposed scenarios are ruled out due to the lack of evidence.
We’d never seen anything like this star,
It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out.
Leading hypothesisBoyajian consider scenarios where the dust originated in a catastrophic collision in an asteroid belt, a giant impact between planets, and a family of comets. Most of the proposed scenarios are ruled out due to the lack of any infrared excess.
Bodman & Quillen investigate the idea of a comet family, but find that they need implausibly-large comets in large numbers, plus a contrived disruption history. Further, the comet hypothesis cannot explain many of the dip light curves.
The most intriguing hypothesis but still a possibility was that this star is home to a technologically sophisticated society that has constructed a so-called Dyson sphere that block light from the star. But the Extraterrestrial Intelligence Institute, SETTI, trained its Allen Telescope Array on the star for more than two weeks, and ruled out an alien structure.
The history of astronomy tells us that every time we thought we had found a phenomenon due to the activities of extraterrestrials, we were wrong.
Institute astronomer Seth Shostak said then.
But although it’s quite likely that this star’s strange behaviour is due to nature, not aliens, it’s only prudent to check such things out.
But earlier this month, the world’s top alien-hunting astronomer refused to rule out the possibility of extraterrestrial megastructure orbiting KIC 8462852 star. Also at that time, SETTI’ researchers states that they were unable to disprove the theory that a massive artificial structure is causing the mysterious light patterns spotted around the distant star.
Something pretty amazing is going on around KIC 8462852 star
Astronomers Bradley E. Schaefer from Louisiana State University takes a different approach to find out more about this star. He looked over a collection of sky photographs in the archives at Harvard College Observatory, a collection which covers the entire sky from 1890 to 1989.
Then he measured 131 magnitudes of KIC 8462852 star from 1890–1989. Results? The star appears to be dimming slowly, over the course of the past century;
KIC 8462852 star displays a secular dimming at an average rate of 0.164 magnitudes per century. This century-long dimming is unprecedented for any main sequence star. Such stars should be very stable in brightness, with evolution making for changes only on time scales of many millions of years.
Previously, the only evidence that KIC 8462852 was unusual in any way was a few dips in magnitude as observed by one satellite, so inevitably we have to wonder whether the whole story is just some problem with Kepler
Implication Within the various dust-occultation ideas, there is some quantity of dust required to create the one deepest dip of 20%: Boyajian and Thompson calculate that the comet family scenario requires 648,000 giant-comets (each with 200 km diameter) to create the century-long fading, all orchestrated to pass in front of the star within the last century — this can be compared to the entire mass of the Kuiper Belt in our own Solar System.
I do not see how it is possible for something like 648,000 giant-comets to exist around one star, nor to have their orbits orchestrated so as to all pass in front of the star within the last century.
So I take this century-long dimming as a strong argument against the comet-family hypothesis to explain the Kepler dips.
So what is going on with this star? We don’t know, we still scratching our heads, I think. It’s a mystery, but an amazing one.
The aliens idea may make this seem silly, but the data are real. Something is going on around KIC 8462852 star. I don’t know what it might be, but what I can guarantee is that when we do figure it out, it’ll be something pretty amazing.
said Phil Plait, Slate’s Bad Astronomy blogger.