Aristarchus of Samos vs astronomer

Aristarchus of Samos and astronomer both are nouns.

Word	Noun	Adjective	Verb	Adverb
Aristarchus of Samos	Yes	No	No	No
astronomer	Yes	No	No	No

Aristarchus of Samos (noun)	astronomer (noun)
an ancient Greek astronomer who was one of the first to propose a heliocentric theory of the universe (circa 270 BC)	a physicist who studies astronomy