The exception is if the companion star is already hidden inside the atmosphere of the red giant causing the asymmetrical shape. (The stars mass is only about 10 to 20 times that of our Sun, and yet it’s diameter, if it was in our solar system, would reach out to the “astroid belt” giving plenty of room for another sun to be hidden inside its red atmosphere)

Perhaps this is the reason that it is so large with very little associated mass is because the two closely revolving objects is stirring up the gas/dust faster than it can fall back into the star. The magnetic induction alone would superheat both objects vaporizing stellar material into what we see. A boiling cauldron of super heated stellar mass.