track star vs superstar

track star and superstar both are nouns.

Word	Noun	Adjective	Verb	Adverb
track star	Yes	No	No	No
superstar	Yes	No	No	No

As nouns, superstar is a hypernym of track star; that is, superstar is a word with a broader meaning than track star:

Other hypernyms of track star include ace, adept, champion, genius, hotshot, maven, mavin, sensation, star, virtuoso, whiz, whizz, wiz, wizard.

track star (noun)	superstar (noun)
a star runner	someone who is dazzlingly skilled in any field