Meaning of ちゃった in Japanese

そこのお店の息子さんが、今度この土地の女の子と出来ちゃった結婚をすることになってる。
Well the son of that shop's family, seems it's come about that he's to have a shot-gun wedding with a local girl.

できちゃった婚のため身内と大学の友人2人しかよばない地味婚にするそうです。
It seems as it was a shot-gun wedding so they're having a quiet wedding with only family and a couple of friends from university invited.