Nu Draconis

Nu Draconis (also known as ν Dra, ν Draconis, where ν is the Greek letter nu, or traditionally as Kuma /ˈkjuːmə/) is a double star in the constellation Draco. The respective components are designated ν¹ Draconis and ν² Draconis. The second component is a spectroscopic binary star system.

This star, along with β Dra (Rastaban), γ Dra (Eltanin), μ Dra (Alrakis) and ξ Dra (Grumium) were Al ʽAwāïd, "the Mother Camels", which was later known as the Quinque Dromedarii.

In Chinese, 天棓 (Tiān Bàng), meaning Celestial Flail, refers to an asterism consisting of ν Draconis, ξ Draconis, β Draconis, γ Draconis and ι Herculis. Consequently, the Chinese name for ν Draconis itself is 天棓二 (Tiān Bàng èr, English: the Second Star of Celestial Flail.)

The two stars of the visual binary are considered to be a common proper motion pair on the basis of their very similar parallaxes, radial velocities, and proper motions, although no orbital motion can be observed.

ν¹ Draconis is an Am star, a slowly rotating chemically peculiar star with abnormally strong metallic absorption lines in its spectrum. Its spectral type of kA3hF0mF0 means that it would have a spectral class of A3 if determined solely from its calcium K lines, F0 if determined from its hydrogen lines, and F0 if determined from other metallic spectral lines.

ν² Draconis is a spectroscopic binary with a period of 38 days. The two stars are separated by 0.267 au on average, and they have an almost circular orbit with an eccentricity of 0.03. The primary is also an Am star, while the secondary has a low mass and luminosity and is only inferred from the orbital movement of the more massive star.