Power Star

Power Stars are stars that provide power to Peach's Castle and the Comet Observatory. They are found only in Super Mario 64, Super Mario 64 DS and Super Mario Galaxy, but a similar item, the Shine Sprite, appears in Super Mario Sunshine.

Super Mario 64 (DS)
In Super Mario 64, there are 120 Power Stars in all, 7 in each of the game's 15 courses, and the remaining 15 are Castle Secret Stars. Super Mario 64 DS has one more star in each course, and 15 more Castle Secret Stars.

Super Mario Galaxy
They are now used to power the Comet Observatory. In this game, there exist several variations of Power Star: Grand Stars, Green Power Stars, and one Red Power Star. There are a total of 242 Power Stars including the types mentioned above, and including playing through the game again as Luigi.