Missing Cat: Striped Fur, Starry Collar

Her breed is a domestic short hair, she has black, grey and white striped fur. The collar was recently changed from the pink one to a navy/black one with stars and moons and on it. She’s a good cat but she likes to be outside, she has since she was a kitten and she always stays in our backyard but this time she didn’t come home. It doesn’t make sense that she just vanished.