The oddest star known in the galaxy is dimming again, and this time it might give up some of its secrets!
“As far as I can tell, every telescope that can look at it right now is looking at it right now.” –Matt Muterspaugh
Of all the 150,000+ stars imaged by NASA’s Kepler, the most bizarre has to be KIC 8462852: Tabby’s Star.
While other stars show small, periodic dips in their brightness due to transiting planets, Tabby’s star shows something unique.
Its dips are much larger in magnitude by up to a factor of 20, and show up irregularly in time.
The only known stars that show such flux dips are very young, with protoplanetary disks surrounding them.
Infrared and ultraviolet observations rule out a protoplanetary disk here; astronomers must consider other explanations.
Perhaps a series of collisions, dusty planets, or extraordinary ringed structures blocks the starlight, but those signals should be periodic.
Perhaps a massive set of disintegrating comets bombards the system, causing an irregular series of dimming events.
But other observations showed that Tabby’s star has dimmed by 20% since 1900, something neither proposal explained.
Perhaps, as many suggested, this was evidence of an alien megastructure being constructed?
But another astrophysical scenario could explain it: a recently devoured planet.
Gases would dim the star overall, while outbursts and flares create irregular flux dips.
A quality light spectrum, taken during the ongoing dimming, could finally discern which model is correct.
Mostly Mute Monday tells the story of an astronomical object, image or phenomenon in visuals, pictures and no more than 200 words.Ethan Siegel is the author of Beyond the Galaxy and Treknology. You can pre-order his third book, currently in development: the Encyclopaedia Cosmologica.