A recent discovery by scientists was that organohalogen freon should indicate the presence of extraterrestrial civilizations on those celestial bodies whose composition includes this gas. By the way, it is widely used on Earth as well: most often it can be found in refrigerators. Freon is contained in the young star IRAS 16293-2422 from the constellation Ophiuchus, and the Rosetta probe discovered it on the comet Churyumov-Gerasimenko.
Organohalogens are composed of fluorine, chlorine, and carbon atoms. Accumulations of these substances appear due to biological activity that occurs in the human body and in some types of fungi. According to researchers, freon is a manifestation of the vital activity of creatures, therefore its presence on space objects indicates the presence of microorganisms or even entire civilizations.
But, alas, this theory was refuted, not having time to properly gain a foothold in the scientific world. The fact is that the ALMA radio telescope, based in the Atacama Desert, found traces of Freon-40 on celestial bodies that a priori could not be inhabited. This telescope also observed the young luminary IRAS 16293-2422, located 400 light years from Earth.
The presence of Freon-40 in lifeless space systems or in very young stars suggests that this organohalogen cannot be considered convincing evidence of the existence of alien life.