How Fast Are These Stars Going Around Andromeda?

Astronomer Vera Rubin and her collaborator are getting ready to point one of the telescopes at Kid Peek to the night sky. They've got this new cutting edge telescope and they're pointing it towards stars at the edge of a spiral galaxy called Andromeda. How fast are these stars going around Andromeda? Up until that point, there was an assumption about how stars and other galaxies would move.