A chemist or astronomer whose speciality is astrochemistry(noun)
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Use "astrochemist" in a sentence
"Ehrenfreund, an astrochemist, is an expert in polycyclic aromatic hydrocarbons, which are known on Earth as a pollutant formed by burning fossil fuels but in astrobiology are important, much-studied players."
"It is precisely in this long sequence of physical and chemical changes that the astrophysicist and the astrochemist can find the means of pushing home their attack."
"Life Beyond Earth - Origin Of Life In The Universe www. youtube.com Carl Edward Sagan, Ph.D. (1934-1996) was an American astronomer, astrochemist, author, and highly successful popularizer of astronomy, astrophysics and other natural sciences."