Theta Cephei, Latinized from θ Cephei, is a stellar class A7, fourth-magnitude star in the constellation Cepheus. This displays at a metallic-line Am star. It is a white-hued, single-lined spectroscopic binary system, located about 127 light-years from Earth. The pair have an orbital period of 914.3 days; the eccentricity was long thought to be low, at 0.03, but recent calculations have put it at a much higher 0.377. They are separated by 4.16 AU. The companion star is calculated to be about 400 times fainter than the primary. It is completely invisible in the spectrum, but is estimated to be a K7 main sequence star. Shared with η Cep, this star system has the title Al Kidr. In Chinese, 天鈎 (Tiān Gōu), meaning Celestial Hook, refers to an asterism consisting of 4 Cephei, HD 194298, η Cephei, α Cephei, ξ Cephei, 26 Cephei, ι Cephei and ο Cephei. Consequently, the Chinese name for θ Cephei itself is 天鈎三 (Tiān Gōu sān, .).