It is the trial galaxy. You need to get 3 green stars.
1. In a dusty dune level. secret pyramid. need to feed star.
2. buble breeze galaxy the pipe.
3. after unlocking luigi, he finds a star. Get his letter.
There is no star mushroom in Super Mario Galaxy 2.
You can't get the red star in super mario galaxy 2
The star from super Mario galaxy is called a luma.
It does once you unlock Yoshi in Yoshi Star Galaxy.
The same as on Super Mario Galaxy 1.
The "star" that floats next to Rosalina is called a 'Luma' the Lumas are from Super Mario Galaxy. And Super Mario Galaxy
in the gateway galaxy
you get every other star and get 100 purple coins on the new galaxy.
You see it in the second power star in Boo Moon Galaxy.
Rainbow Road includes some Mario Galaxy aspects, such as star bits. Also if you have a save file on your Wii with Super Mario Galaxy and Mario Kart Wii you can get a character.
You get every green star.
The Red Star powerup from Super Mario Galaxy is not in the sequel.