Researchers with a collective term for the scientific search for intelligent extraterrestrial life have pointed their telescopes in the direction of a star system 94 light-years away for possible intelligent inhabitants.
The star system, HD 164595, is a few billion years older than the Sun but centered on a star of comparable size and brightness. It is the purported source of a signal found with the RATAN-600 radio telescope in Zelenchukskaya, at the northern foot of the Caucasus Mountains, by a group of Russian astronomers.
"This system is known to have one planet, a Neptune-sized world in a very tight orbit, making it unattractive for life," said Seth Shostak, senior astronomer at the Search for Extraterrestrial Intelligence (SETI) Institute in Mountain View, northern California, wrote in a blog on the institute's website. "However, there could be other planets in this system that are still undiscovered."
The signal from the constellation Hercules was received on May 15, 2015, and first reported in recent days on the Centauri Dreams website, which covers research on deep space exploration.
It has been discussed in a presentation given by several Russian astronomers as well as Italian researcher, Claudio Maccone, the chair of the International Academy of Astronautics Permanent SETI Committee.
About whether the signal could be a transmission from a technically proficient society, Shostak acknowledged that "at this point, we can only consider what is known so far."
Shostak noted that there are a number of questions to be answered, about the direction of the signal and the characteristics of the signal itself, plus whether and why it is targeted at our solar system.
The wavelength of the reported signal is 2.7 cm, equivalent to a frequency of 11 GHz; the beam is about 20 arcsec by 2 arcmin.
"The chance that this is truly a signal from extraterrestrials is not terribly promising, and the discoverers themselves apparently doubt that they've found ET," Shostak wrote, "nonetheless, one should check out all reasonable possibilities, given the importance of the subject."
ET, short for Extra-Terrestrial, is the name of a popular American science fiction fantasy film released in 1982, and the scene of the story was set at a suburban California location on the U.S. west coast.
To pursue the lead of what researchers call "a candidate signal," the Allen Telescope Array (ATA) was swung in the direction of HD 164595 beginning on the evening of August 28. However, according to Shostak, it has so far not found any signal anywhere in the very large patch of sky covered by the ATA.
The ATA, formerly known as the One Hectare Telescope (1hT), is a radio telescope array situated at the Hat Creek Radio Observatory, 470 km northeast of San Francisco, California. The project was originally developed as a joint effort between the SETI Institute and the Radio Astronomy Laboratory (RAL) at the University of California, Berkeley.
Shostak said researchers intend to cover the big swath of the radio frequencies in the next day or two and continue to monitor the star system with the telescope array.
"So what's the bottom line? Could it be another society sending a signal our way? Of course, that's possible," Shostak wrote, adding that "however, there are many other plausible explanations for this claimed transmission - including terrestrial interference. Without a confirmation of this signal, we can only say that it's 'interesting.'"
