Owen Lars and Beru Whitesun raised Luke Skywalker. But had they adopted him?
Luke calls them uncle Owen and aunt Beru. He knew of the family relation between Owen and his father, Anakin.
Yet the Skywalker family tree on Wikipedia (since corrected) shows a dashed line from Bail and Breha Organa to Leia, representing the adoption, but shows no such line from Owen Lars and Beru Whitesun to Luke Skywalker.
Had Luke Skywalker been adopted by Owen and Beru? Was there any need to formally adopt him?