My☆Star Imōto☆Planet (マイ☆スタ 妹☆星) or My Star Imōto Planet is the second fictional work by Kirino under the pen name "Rino". It is briefly seen in the seventh episode of the anime. Kyosuke had to read it as life counseling punishment for viewing porn sites on Kirino's computer. It's about a girl(who is actually Kirino) traveling into space and landing on a planet of little sisters. She ends up doing "amazing things" (though what these "amazing things" were was never actually specified). Kirino eventually turned it into the light novel publisher Raigeki Bunko and it was considered good enough to become a book, but Kirino felt like it was finished.
It was discarded by Kirino for Imōtoshi.