Luma, known in Japan as Chiko (チコ), is a species of star-like creatures that first appeared in Super Mario Galaxy. Unlike most Stars, they have a tear drop-like shape, and come in many colors. They are much like Power Stars, but they are more circular in shape and able to talk. Lumas boast the ability to transform, from minor objects to entire galaxies. They seem to acknowledge Rosalina as their "mama". Most of them make their home in the Comet Observatory.
The Lumas appear in Super Mario Galaxy, living on the Comet Observatory with Rosalina, and supporting Mario with his journey to save Princess Peach. In the end, all the Lumas sacrifice themselves to destroy the massive black hole created by Bowser's dying sun. However, Luma is reborn and lives on a small planet, while it is hinted that all of the other Lumas will be reborn later. In Mario Kart Wii, a Yellow Luma is around Rosalina at all times, but it has no effect on gameplay. In Super Mario Galaxy 2, the Lumas serve a similar role as to the prequel. However, the purple Luma is absent, there are now Giant Lumas which are simply overgrown Yellow Lumas, there is an orange Co-Star Luma which acts as Player 2, and the Green Lumas just simply look forward to seeing the Green Power Stars. Lumas reappear in Super Mario 3D World on the level Super Galaxy of World Star. Many Lumas can be seen flying around the level and Rosalina can be seen at the end. A Luma appears in Super Smash Bros. for Nintendo 3DS and Wii U with Rosalina, who is a new playable character in the game. The Luma assist Rosalina in some of her attacks.
Several Lumas appear as background characters in the Starship Mario, from Galaxy Tours, as background characters. Lumas wander back and forth and do not interfere in the matches at all, they also come in various colors, ranging from yellow to orange. One black Luma, called Polari, also wanders the Starship, despite never making an actual appearance in said location on its source games.