I swear Harvard have simply been trolling space science the past couple of years. The last big one being when they claimed that 'Oumaumau might have been part of a space ship!
In this instance, it's all about the Oort Cloud - a theoretical shell of ice and rock at the very edge of the solar system. We haven't observed it, or even begun to calculate anything reliable about it.
But now Harvard are suggesting that the only way that a particular view of the Oort Cloud can be satisfied is if the Sun formed as a binary pair. Yet they fail to explain how a twin star can be pulled away by the nearby gravity of other forming stars, without taking most of the Oort Cloud with it!