SETI’s Allen Telescope Array Fails to Detect “ET Megastructure” Signals From Star System KIC 8462852

 

 

Array

 

Could there be intelligent life hanging out in the vicinity of the star system KIC 8462852? The strange and strong dimming of this star has encouraged speculation that a technologically sophisticated civilization has built megastructures in orbit there. Given this possibility, the SETI Institute has trained its Allen Telescope Array situated in the High Sierra's on this star for more than two weeks. Finding a signal would be a strong indication for the presence of intelligence.


Two different types of radio signals were sought: (1) Narrow-band signals, of order 1 Hz in width, such as would be generated as a “hailing signal” for societies wishing to announce their presence. This is the type of signal most frequently looked for by radio SETI experiments. (2) Broad-band signals that might be due to beamed propulsion within this star system. If astroengineering projects are really underway in the vicinity of KIC 8462852, one might reasonably expect the presence of spacecraft to service this activity. If these craft are propelled by intense microwave beams, some of that energy might manifest itself as broad-band radio leakage.

“This is the first time we’ve used the Allen Telescope Array to look for relatively wide-band signals, a type of emission that is generally not considered in SETI searches,” said SETI Institute scientist Gerry Harp.

The world's astronomy community has been keeping a close eye on the strange star, discovered last year by Tabetha Boyajian, a postdoctoral fellow at Yale University, which has dimmed dramatically numerous times over the past few years, dropping in brightness by up to 22 percent. These events have triggered a viral global conversation that the star may be surrounded by some type of alien megastructure, a Dyson-sphere type object— a hypothesis that will be put to the test if and when KIC 8462852 dims again, according to Jason Wright, an astronomer at Pennsylvania State University.

 

Kepler-field-of-view

 

 

"As long as one of those events occurs again, we should be able to catch it in the act, and then we'll definitely be able to figure out what we're seeing," Wright told Space.com. Last year, Wright met Boyajian at a talk she gave at the Center for Exoplanets and Habitable Worlds. After the seminar she spoke to Wright and showed him a star spotted from the Kepler telescope data by her and her team. “The search for extraterrestrial intelligence doesn’t have many good targets to look at, so this seems like the best one,” Wright said.

Analysis of the Allen Array data show no clear evidence for either type of signal between the frequencies of 1 and 10 GHz. This rules out omnidirectional transmitters of more than approximately 100 times today’s total terrestrial energy usage in the case of the narrow-band signals, and ten million times that usage for broad band emissions.

While these limits are relatively high, a fact due primarily to the large distance of KIC 8462852 (about 1500 light-years), there’s this to consider: If aliens are deliberately targeting our part of the galaxy, the necessary transmitter power for detection becomes very much less. In addition, any beings able to build such large structures will have access to far more energy than a fossil-fueled society like our own.

Observations will continue, but so far no evidence of deliberately produced radio signals has been found in the direction of KIC 8462852.

This work can be found at http://arxiv.org/abs/1511.01606

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