NASA's Spitzer Space Telescope sheds light on "alien megastructure" star
KIC 8462852 recently attracted a lot of attention owing to speculation that dramatic dips in the star's lightthat were detected in 2011 and 2013 by NASA's Kepler spacecraftwere due to the presence of vast superstructures created by an advanced alien race. But a new study centering around analysis of data collected by NASA's Spitzer Space Telescope suggests that the mysterious objects occulting the star KIC 8462852 aren't the creations of little green men, but in fact a family of comets.
This alien megastructure theory that recently made news across the globe prompted SETI to task its Allen Telescope Array (ATA) to take readings onthe peculiar star. But so far, the ATA has come upempty, leaving the tantalizing mystery as to the causeof the unusual readings open for debate.
From the outset themajority of the scientific community had stuck to more level ground,instead pointing to possible clouds of debris created from an impactbetween two large bodies, or the presence of comets as the leadingcauses of the occultation.
If the strangeoccultation observed around KIC 8462852 were to be the result ofdebris from colliding planetoids or asteroids passing in front of thestar, then the fragments would be at temperatures that would causethem to emit infrared light. Therefore, the theory could be tested bytaking aim at the star with an infrared telescope.
Previous observationscarried out by Kepler had detected the phenomenon in the visiblelight spectrum, and so to test the collision theory astronomersanalyzed infrared data collected by the Spitzer space telescope,which had by chance taken readings on KIC 8462852 earlier this year.
An analysis of the datafailed to find any excess of infrared light that would point towardplanetary/asteroid debris as the cause of the dimming. This lack ofevidence places the theory that the dimming of light from KIC 8462852was caused by a family of comets traveling in a highly eccentricorbit.
This theory is supportedby the lack of infrared light picked up in the Spitzer data, as, unlike the warmer impact fragments that would result froma collision, the presence of comets would be nigh on impossible todetect.
In order to explain theunusual occultation pattern, astronomers assert that an enormous leadcomet could have been responsible for the original dimming of lightdetected in 2011, while the 2013 event was the result of a swarm oflesser comets following in the giant's wake.
While this seems likethe most likely explanation, the new evidence pointing to the comettheory is far from conclusive, with further observation needed to reveal the source of the occultation.
"We may not know yet what's going on around this star," says Massimo Marengo of Iowa State University who led this latest study. "But that's what makes it so interesting."
A paper on the findingshas been accepted for publication in the Astrophysical Journal Letters.