My initials are PQRS. Now tell me, what do I mean? Who am I ?

I live above a star, but I do not burn.
I have 11 friends, but they do not turn.
I am visited in sequence: never, once, or repeatedly.
My initials are PQRS.
Now tell me, what do I mean?
Who am I ?

Answer : Number 7 on a Feature Phone Keypad