astronomy vs come up

astronomy is a noun but come up is not a noun.

Word	Noun	Adjective	Verb	Adverb
astronomy	Yes	No	No	No
come up	No	No	Yes	No

astronomy (noun)	come up (noun)
the branch of physics that studies celestial bodies and the universe as a whole

astronomy (verb)	come up (verb)
	result or issue
	start running, functioning, or operating
	gather or bring together
	gather (money or other resources) together over time
	bring forth, usually something desirable
	come up, of celestial bodies
	come to the surface
	move toward, travel toward something or somebody or approach something or somebody
	move upward
	get something or somebody for a specific purpose
	originate or come into being
	be mentioned