Another misleading headline!
But as a UFO sceptic I am glad I read the article. There is a fallacies, however, at the beginning. Molecular structure is fully determined by the electrons attracted by the protons in the nucleus; it is totally unaffected by the number of neutrons in the nucleus. So isotope ratios have zero relevance to the molecular structures that the atoms form.
(They can effect its weight and its radioactive.)