Southern Ocean is littered with rubbish
It is well documented that the southern Indian Ocean is littered with waste, so it is more than likely these satellite images are just that.
Is perhaps likely that this is a reoccurrence of something similar to the Adam air crash in Indonesia? Flight crew distracted by inflight-non-serious failure of a particular system and they simply forgot to fly the plane? In the case of the Adam Air crash the aircraft wasn't found for sometime!