'I am Ramandu[,' replied the Old Man, '[But I see that you stare at one another and have not heard this name. And no wonder, for the days when I was a star had ceased long before any of you knew this world, and all the constellations have changed.'Who else is a former star?
'Golly,' said Edmund under his breath. 'He's a retired star.'
'Aren't you a star any longer?' asked Lucy.
'I am a star at rest, my daughter,' answered Ramandu. 'When I set for the last time, decrepit and old beyond all that you can reckon, I was carried to this island. I am not so old now as I was then. Every morning a bird brings me a fire-berry from the valleys in the sun, and each fire-berry takes away a little of my age. And when I have become as young as the child that was born yesterday, I shall take my rising again (for we are at earth's eastern rim) and once more tread the great dance.'
'In our word,' said Eustace, ' a star is a huge ball of flaming gas.'
'Even in your world, my son, that is not what a star is but only what it is made of. And in this world you have already met a star: for I think you have been with Coriakin.'
'Is he a retired star, too?' said Lucy.
'Well, not quite the same,' said Ramandu. 'It was not quite as a rest that he was set to govern the Duffers. You might call it a punishment. He might have shone for thousands of years more in the southern winter sky if all had gone well.'
'What did he do, Sir?' asked Caspian.
'My son,' said Ramandu, 'it is not for you, a son of Adam, to know what faults a star can commit.' (Dawn Treader 208-9)
I can think of two off the top of my head.
Mrs. Whatsit from Madeleine L'Engle's A Wrinkle in Time, one of my favorite books of all time, and I believe the only favorite book I share with my mother. Mrs. Whatsit had given up her starhood by the time Meg (the book's protagonist) meets her. The former star was a very warm character, who tried very hard to be (or seem) human, even if she was sometimes a little off.
Stars could go bad in Mrs. Whatsit's world, too. (It's been over a year since I reread this one, so I'm not completely positive.)
And also, Yvaine from Neil Gaiman's Stardust. Of course, it was Yvaine's destiny to be knocked out of the sky and find her true love, but first she was a star. She glowed a little when she was happy, but I don't remember if that was in the book or just in the movie.
As I recall, neither of Mrs. Whatsit nor Yvaine could ever become a star again (ie. no fire-berries for them). It was tragic for them both but wonderfully rich for the story.
In other news, The Voyage of the Dawn Treader is going to be a movie! I saw the other two. While the first one was my favorite, and I liked the second one too, I'm incredibly excited for this one. It was my favorite when I was very young. I think it was the spirit of exploration that I loved.
Sadly, I think the earliest it comes out would be December. Sigh...