It's gotta be the left one. The colors of its eyes gives more heat energy and white ones just gives 0.5 heat energy. Technically when the color of the aura on the eyes and the body itself gives more energy according to my brain that's definitely smart can tell enough that the left one of the Purple Star which is named "The Horizon Star" is more energy then the other Purple Star which is also named "Purr Pael" which gives less energy. Therefore, left star wins.