▁on ▁its ▁low ▁al bed o , ▁measured ▁by ▁the ▁W ide - field ▁Inf ra red ▁Survey ▁Explorer ▁( WI SE ), ▁Ra ab ▁is ▁possibly ▁C - type ▁astero id . ▁ ▁Rot ation ▁period ▁▁ ▁In ▁December ▁ 2 0 1 1 , ▁a ▁rot ational ▁light cur ve ▁of ▁Ra ab ▁was ▁obtained ▁from ▁phot ometric ▁observations ▁in ▁the ▁R - band ▁by ▁astronom ers ▁at ▁the ▁Pal om ar ▁Trans ient ▁Factory ▁in ▁California . ▁Light cur ve ▁analysis ▁gave ▁a ▁rotation ▁period ▁of ▁ 2 7 4 . 9 4 4 ▁hours ▁with ▁a ▁bright ness ▁amplitude ▁of ▁ 0 . 0 9 ▁magnitude . ▁However , ▁the ▁light cur ve ▁is ▁only ▁fragment ary ▁and ▁could ▁be ▁completely ▁wrong ▁( ). ▁This ▁makes ▁Ra ab ▁only ▁a ▁potentially ▁slow ▁rot ator ▁rather ▁than ▁a ▁confirmed ▁one . ▁As ▁of ▁ 2 0 1 8 , ▁no ▁follow ▁up ▁observations ▁have ▁been ▁published . ▁ ▁Diam eter ▁and ▁al bed o ▁▁ ▁According ▁to ▁the ▁surve ys ▁carried ▁out ▁by ▁the ▁Japanese ▁Ak ari ▁satellite ▁and ▁the ▁NE OW I SE ▁mission ▁of ▁NASA ' s ▁W I SE ▁teles ec ope , ▁Ra ab ▁measures ▁between ▁ 1 5 . 2 8 ▁and ▁ 1 9 . 2 8 0 ▁kilom eters ▁in ▁diameter ▁and ▁its ▁surface ▁has ▁an ▁al bed o ▁between ▁ 0 . 0 3 6 ▁and ▁ 0 . 0 8 6 . ▁ ▁The ▁Coll abor ative ▁Ast ero id ▁Light