A trans-Neptunian object known as 2002 TC302 appears to have a large moon at an unusually close orbit
Source:
https://www.newscientist.com/article/2244260-a-large-moon-might-be-hugging-an-object-in-the-outer-solar-system/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home