(Image: Big Ear Radio Observatory and North American AstroPhysical Observatory)
An amateur astronomer found 15 stars suitable for the role of the source of the Wow! Radio signal.
The most curious candidate among the found objects was a sun-like star located 1801 light years from the Sun, which may be a good target for further search for planets.
To date, the most unusual candidate for signals sent by other intelligent civilizations is the famous Wow! Signal.
It was recorded in August 1977 by the astronomer Jerry Ehman as part of the SETI project using one of the antennas of the Big Ear radio telescope at the Ohio State University.
The signal was intense, narrow-band and lasted 72 seconds, which corresponded to the theoretical concepts of a signal sent by an extraterrestrial intelligence.
However, many years of attempts to detect a signal repetition using ground-based observatories did not yield any results, which raised doubts about its artificial nature.
Various hypotheses have been put forward about the nature of the Wow! signal, including pulsars, rotating exoplanets, earth signal reflections from space debris and cometary coma, but none of them was ultimately accepted.
So, an Amateur astronomer Alberto Caballero decided to determine the possible source of the mysterious signal.
He proceeded from the assumption that if the source was another form of life, then, most likely, it “lives” on an Earth-like exoplanet orbiting a sun-like star.
The second requirement for the source, which is deduced from the Drake equation, was that another civilization cannot be closer than 500 light years from the Sun. In this case the probability of detecting another intelligence is practically zero.
Then Caballero searched in the Gaia space telescope database, which contains information on the properties and positions of the stars in the Milky Way.
The sample contained 66 stars of spectral types from K to G, which were located in two small regions in the constellation of Sagittarius, from where the signal could come.
(Star 2MASS 19281982-2640123 / PanSTARRS)
Among them, the astronomer was looking for stars with a radius of 0.83 to 1.15 of the solar radius, an effective temperature of 4450 to 6000 kelvin and a luminosity of 0.34 to 1.5 of the solar luminosity.
As a result, 15 interesting candidates were found, but the most interesting was the star 2MASS 19281982-2640123, located at a distance of 1801 light years from the Sun.
It has a radius of 0.996 that of the Sun, a luminosity of 1.0007 of the Sun's luminosity, and an effective temperature of 5783 Kelvin.
Caballero believes that this object can be considered a good target for study in order to more accurately determine its properties and search for exoplanets or a companion star.
However, it should be considered that the sample did not include faint stars, stars whose properties are poorly understood, and extragalactic sources, thus the question of the nature of the Wow! still remains open.
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