asteroid vs star-shaped

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

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

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

asteroid (noun)	star-shaped (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)

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