> "To elaborate, the star that died and turned into a black hole would have been at least 20 times as massive as the Sun. This likely means that it must have lived only for a few million years. But, if both stars formed at the same time, the gigantic one would have puffed up and swallowed the other star before it could become a "proper, hydrogen-burning, main-sequence star like our Sun". Or, if the star survived, it should have been on a much tighter orbit."
https://interestingengineering.com/science/closest-black-hol...
> "To elaborate, the star that died and turned into a black hole would have been at least 20 times as massive as the Sun. This likely means that it must have lived only for a few million years. But, if both stars formed at the same time, the gigantic one would have puffed up and swallowed the other star before it could become a "proper, hydrogen-burning, main-sequence star like our Sun". Or, if the star survived, it should have been on a much tighter orbit."