Kochab ya kai wani matsayi a cikin juyin halittarsa inda murfin waje ya fadada zuwa sau 42 na kewayon Rana. Wannan fadada yanayin yana haskaka 390 sau da yawa kamar yadda hasken rana yake daga yanayin waje a zafin jiki mai tasiri na 4,030 K. Wannan zafi yana ba da tauraron haske mai launin ruwan hoda na tauraron K-type. Ta hanyar yin samfurin wannan tauraron bisa ga hanyoyin juyin halitta, za a iya kiyasta nauyin wannan tauraron a matsayin 2.2 ± 0.3 na Sun. Ƙididdigar taro ta amfani da radius na wannan tauraron da aka auna ta hanyar amfani da ma'auni da aka ƙayyade ta hanyar ma'auni yana samar da ƙananan nauyin hasken rana na 2.5 ± 0.9.
K4 na uku