4 , ▁Brian ▁Warner ▁at ▁his ▁Pal mer ▁Div ide ▁Observ atory ▁, ▁Colorado , ▁published ▁an ▁ambigu ous ▁period ▁of ▁ ▁and ▁ ▁hours ▁with ▁an ▁amplitude ▁of ▁ ▁and ▁ ▁magnitude , ▁respectively , ▁depending ▁on ▁whether ▁the ▁period ▁solution ▁is ▁derived ▁from ▁a ▁mon om od al ▁or ▁from ▁a ▁b im od al ▁light cur ve ▁( ). ▁Alternatively , ▁Warner ▁also ▁gave ▁a ▁re vised ▁period ▁of ▁ ▁hours ▁and ▁an ▁amplitude ▁of ▁ ▁magnitude ▁for ▁his ▁other ▁observation ▁taken ▁on ▁December ▁ 2 0 0 0 . ▁ ▁In ▁February ▁ 2 0 1 1 , ▁James ▁Br ins field ▁at ▁the ▁Via ▁Cap ote ▁Observ atory ▁ ▁in ▁California ▁measured ▁a ▁period ▁of ▁ ▁hours ▁with ▁an ▁amplitude ▁of ▁ ▁magnitude ▁( ). ▁Observ ations ▁by ▁Nicolas ▁Es se iva ▁and ▁Ra oul ▁Be hr end ▁in ▁December ▁ 2 0 1 4 ▁gave ▁a ▁tent ative ▁period ▁of ▁ ▁hours ▁and ▁a ▁weak ▁amplitude ▁of ▁ ▁magnitude ▁( ). ▁A ▁basically ▁identical ▁period ▁of ▁ ▁hours ▁with ▁a ▁bright ness ▁variation ▁of ▁ ▁magnitude ▁was ▁determined ▁by ▁French ▁amateur ▁astronom er ▁René ▁Roy ▁in ▁February ▁ 2 0 1 1 ▁( ). ▁In ▁March ▁ 2 0 1 6 , ▁the ▁Spanish ▁group ▁of ▁astero id ▁obser vers , ▁O B AS , ▁measures ▁a ▁period ▁of ▁ ▁hours ▁with ▁an ▁amplitude ▁of ▁ ▁magnitude ▁( ). ▁ ▁Diam eter ▁and ▁al bed o ▁▁ ▁According ▁to ▁the ▁surve ys ▁carried ▁out ▁by ▁the ▁NE