Rigel, the blue supergiant at Orion's foot

Rigel marks Orion's foot. It is a blue-white supergiant and usually the brightest star in Orion, even though it carries the second Greek letter, beta.

Where is it from where I am?

How to spot it: The bright blue-white star at the opposite corner of Orion from Betelgeuse. Source (opens in a new tab)

What you are looking at

Jim Kaler (opens in a new tab) describes Rigel as a class B8 supergiant with a surface near 11,500 kelvin, about 74 times the Sun's radius, shining with the light of some 85,000 Suns once its ultraviolet is counted. He gives its distance as 860 light-years, from the second reduction of the Hipparcos data, and ranks it seventh in brightness.

Beta, but brighter

Greek letters usually run in order of brightness, but Rigel, beta Orionis, is normally brighter than Betelgeuse, alpha. Kaler suggests (opens in a new tab) two explanations: variable Betelgeuse may have been near its brightest when the letters were assigned, or Johann Bayer simply went by position.

A name from Arabic

The name comes from rijl al-jauza, "the foot of al-jauza" (opens in a new tab), the Arabic name for the figure. In Māori tradition the same star is Puanga, which some iwi watch for the new year.

Not alone, and not finished

A seventh-magnitude companion sits nine seconds of arc away (opens in a new tab), itself a pair, but Rigel's glare makes it hard to see in a small telescope. Stellar theory expects Rigel to swell into a red supergiant like Betelgeuse and, eventually, to explode.

Where on Earth, and when

It rises from anywhere south of about 82°N.

South of about 82°S, it never sets.

It climbs at least 20° high, the finder's threshold for a suggestion, from latitudes between 78°S and 62°N.

It is highest in the evening sky, at about 9 p.m. local time, in mid-January, from either hemisphere, wherever it rises. With daylight saving time, that is nearer 10 p.m. on the clock.

Worked out by this site from the Bright Star Catalogue, for a flat, clear horizon. Hills, buildings, haze and city light all cut into this; the air also lifts objects near the horizon by about half a degree. For your own place and night, use the sky finder.