star-shaped vs asteroid

star-shaped is not a noun while asteroid is a noun.

Word	Noun	Adjective	Verb	Adverb
star-shaped	No	Yes	No	No
asteroid	Yes	Yes	No	No

As adjectives, star-shaped and asteroid are synonyms defined as:

star-shaped (noun)	asteroid (noun)
	any of numerous small celestial bodies composed of rock and metal that move around the sun (mainly between the orbits of Mars and Jupiter)

star-shaped (adjective)	asteroid (adjective)
shaped like a star	shaped like a star