track star vs star

track star and star both are nouns.

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

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

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

track star (noun)	star (noun)
a star runner	the topology of a network whose components are connected to a hub
	a star-shaped character * used in printing
	(astronomy) a celestial body of hot gases that radiates energy derived from thermonuclear reactions in the interior
	any celestial body visible (as a point of light) from the Earth at night
	an actor who plays a principal role
	someone who is dazzlingly skilled in any field
	a performer who receives prominent billing
	a plane figure with 5 or more points; often used as an emblem

track star (adjective)	star (adjective)
	indicating the most important performer or role