3 7   AU ). ▁Other ▁mid - s ized ▁cub ew anos ▁follow ▁similar ▁or bits ▁as ▁well , ▁not ably ▁ ▁and ▁. ▁ ▁It ▁has ▁been ▁observed ▁ 3 0 3 ▁times , ▁with ▁prec overy ▁images ▁back ▁to ▁ 1 9 5 4 . ▁ ▁Size ▁▁ ▁In ▁ 2 0 0 4 , ▁the ▁non - d ete ction ▁of ▁IR ▁thermal ▁em issions ▁put ▁an ▁upper ▁limit ▁of ▁ ▁on ▁its ▁diameter ▁and ▁a ▁lower ▁limit ▁on ▁the ▁al bed o ▁of ▁ 0 . 1 9 . ▁In ▁a ▁ 2 0 0 6 ▁International ▁Astronom ical ▁Union ▁press ▁release ▁discuss ing ▁the ▁I AU ▁ 2 0 0 6 ▁draft ▁proposal , ▁a ▁diagram ▁suggested ▁that ▁ ▁could ▁be ▁as ▁large ▁as ▁ 5 0 0 0 0 ▁Qu ao ar . ▁The ▁artist ' s ▁diagram ▁was ▁largely ▁based ▁on ▁the ▁concept ▁that ▁, ▁with ▁an ▁absolute ▁magnitude ▁( H ) ▁of ▁ 3 . 4 , ▁may ▁have ▁an ▁al bed o ▁around ▁ 0 . 0 8 , ▁which ▁resulted ▁in ▁an ▁over ly ▁optim istic ▁diameter ▁estimate ▁of ▁around ▁. ▁ ▁In ▁ 2 0 0 7 , ▁measurements ▁by ▁the ▁Sp itzer ▁Space ▁T eles cope ▁showed ▁that ▁it ▁may ▁be ▁less ▁than ▁ ▁in ▁diameter . ▁In ▁ 2 0 0 8 , ▁it ▁was ▁considered ▁to ▁be ▁a ▁d war f ▁planet ▁based ▁on ▁its ▁light cur ve ▁amplitude ▁and ▁the ▁assumption ▁that ▁it ▁was ▁larger ▁than ▁