Ok so here goes: 1985 or so. I never held this book in my hands, it was a book on tape. The tape was clear and inside the cassette, there were purple discs (shiny, lavender color purple) around where the parts turn inside the tape player. The narrator was female. It was about a young (maybe 10 years old?) girl and her parents. They lived on a planet that was purple. I think there was something about space travel but I’m not sure. The girl either gets separated from her parents or leaves to go exploring… perhaps gets lost. I don’t really remember what happens while she is gone from her parents but I have a very strong memory towards the end of the story of a purple sun rising over the purple planet. It was kind of a feel good story. Solved! The Purple Planet Phatos by Trenna Sutphen