Lambda_Draconis
Lambda Draconis
Star in the constellation Draco
Lambda Draconis (λ Draconis, abbreviated Lam Dra, λ Dra), also named Giausar (/ˈdʒɔːzɑːr/ JAW-zar),[13][14] is a solitary,[15] orange-red[16] star in the northern circumpolar constellation of Draco. It is visible to the naked eye with an apparent visual magnitude of +3.85.[2] Based upon an annual parallax shift of 9.79 mas as seen from the Earth,[1] the star is located around 333 light years from the Sun.
This is an evolved red giant star on the asymptotic giant branch[3] with a stellar classification of M0III-IIIa Ca1.[4] It is a suspected slow irregular variable with a periodicity of roughly 1,100 days.[5] The measured angular diameter, after correction for limb darkening, is 6.43±0.07 mas.[17] At the estimated distance of the star, this yields a physical size of about 53 times the radius of the Sun.[9] It has an estimated 1.7[8] times the mass of the Sun and is radiating 834 times the solar luminosity from its photosphere at an effective temperature of 3,958 K.[10]