Curated by RSF Research Staff
Solving Kepler’s Most Enigmatic Find
In September 2015, an amateur astronomer D. M. LaCourse and Tabetha Boyajian, an assistant professor, have discovered the star KIC 8462852 using the public data from the Kepler telescope. Situated in the cluster NGC 6866, this star called “Tabby’s Star” is very particular due to a significant instant dimming that can be due to large irregular objects transiting. But the dimming is so large (20%) that it cannot be explained with planets. Molecular clouds are also ruled out because of the absence of excessive IR emissions. Super huge comets may explain this, but one possibility that remains open is some huge structure built by aliens for whatever reason traversing the star.
Dimming stars are interesting for multiple reasons. One of them is that a dimming pattern is how we find exoplanets. When a planet passes between us and its host star as it orbits, the light of the star dims from our perspective. Therefore, the Kepler telescope spends a lot of time looking for these dimming stars.
Usually, exoplanet dimming is regular and periodic and limited. But, in the case of KIC 8462852's dimming is irregular, and the amount it dims varies. It seems to have been on a very slow fade, dimming gradually over time. Trying to explain this, a lot of theories were proposed like a ringed planet passing in front of the star, either absolutely enormous or a smaller one with an orbital wobble; a swarm of comets; space junk; aliens structure, the star swallowing a planet, something happening inside the star itself, or simply an instrument glitch. At this point, no theory had passed the various confirmation tests and the question is still open.
“This [dimming] behavior was not something we were looking for or had trained our algorithms to find. In fact, we were first alerted to the star’s unique activity by citizen scientists participating in the Planet Hunters program. […] To learn more, we needed to catch it in action again. It just comes down to that. We can't rule anything out completely until the evidence warrants it. This kind of patiently executed, coordinated monitoring at multiple wavelengths will unlock this mystery eventually."
Tabetha Boyajian, assistant professor of astrophysics at Louisiana State University, Baton Rouge