calculated an upper limit for these mega-mammoth masses. Fifty billion suns, that's 100 000 000 000 000 000 000 000 000 000 000 000 000 000 kg, otherwise known as "ridiculously stupidly big" I like descriptions like that, for the non-scientist 1040kg means absolutely nothing ... but Ridiculously Stupidly Big puts it all into perspective :)
/grin