Scientists worldwide turn telescopes to "alien megastructure" star – The Space Reporter

Artist’s illustration showing a cloud of comet fragments blocking light from a star—one of the possible explanations for the strange, occasional dimming of KIC 8462852, also known as “Tabby’s Star.” Credit: NASA/JPL-Caltech

The star that has stumped astronomers with an irregular pattern of dimming and brightening that some have attributed to a possible surrounding “alien megastructure” was observed by astronomers worldwide after it was found to have suddenly become three percent dimmer.

KIC 8462852, also known as “Tabby’s Star” due to the discovery of its brightness changes by astronomer Tabetha Boyajian, experiences atypical brightness changes that cannot be attributed to the transit of an orbiting planet.

NASA’s Kepler Space Telescope, which uses the transit method to locate planets passing in front of their stars, initially observed the strange changes in the brightness of Tabby’s Star in September 2015.

Unable to explain these changes, scientists considered a variety of possible causes, including powerful magnetic activity, a comet swarm, or even a possible megastructure built around the star by an intelligent alien civilization.

Observing the star as it undergoes dimming would enable scientists to measure its spectra, but such observations cannot be planned because the phenomenon is unpredictable.

“Whatever’s causing the star to get dimmer will leave a spectral fingerprint behind,” noted Jason Wright of Pennsylvania State University.

“So if there is a lot of dust between us and the star…it will block more blue light than red light. If there is gas in that dust, that gas should absorb very specific wavelengths, and we should be able to see that.”

An object’s spectrum can also show whether it is traveling toward or away from an observer.

When Boyajian at the Fairborn Observatory in Arizona detected the star’s dimming at 4 AM on Friday, May 19, she immediately put out a call to both professional and amateur astronomers to point as many telescopes as possible at the star.

Wright, who is leading a study of the star and was among the scientists contacted, conducted a live webcast of the event on Friday at 2 PM EDT (1800 GMT).

KIC 8462852’s dimming was seen by multiple observatories.

In response to the call, the twin 10-meter telescopes at the W.H. Keck Observatory in Hawaii have been trained on the star, as has the Breakthrough Listen Initiative‘s Automated Planet Finder telescope at Lick Observatory in California.

Researchers hope to gain time on three other big telescopes in the US, as well as on the Green Bank radio telescope in West Virginia in their quest to unravel the mystery.

Scientists worldwide turn telescopes to "alien megastructure" star – The Space Reporter