Leo contains many bright shining stars , such as Regulus ( also called Î Leonis ) ; the lion 's tail , Denebola ( also called Î Leonis ) ; and Î 1 Leonis ( also called Algieba ) . Leo contains many bright shining stars , such as Regulus ( Î Leonis ) ; the lion 's tail , Denebola ( Î Leonis ) ; and Î 1 Leonis ( Algieba ) .