You are using an outdated browser. Please upgrade your browser to improve your experience and security.
Polaris
star
Media
Print

Polaris

star
Alternative Title: Alpha Ursae Minoris

Polaris, also called Alpha Ursae Minoris, Earth’s present northern polestar, or North Star, at the end of the “handle” of the so-called Little Dipper in the constellation Ursa Minor. Polaris is actually a triple star, the brighter of two visual components being a spectroscopic binary with a period of about 30 years and a Cepheid variable with a period of about 4 days. Its changes in brightness are too slight to be detected with the unaided eye. Apparent visual magnitude of the Polaris system is 2.00. See also polestar.

View of the Andromeda Galaxy (Messier 31, M31).
Britannica Quiz
Astronomy and Space Quiz
When did the Space Age begin?
This article was most recently revised and updated by Amy Tikkanen, Corrections Manager.
Check out Britannica's new site for parents!
Subscribe Today!
免费a级毛片_成 人影片 免费观看网站_骚虎