Science & history · Star guide
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.
About this picture
NASA/Goddard Space Flight Center Scientific Visualization Studio. Gaia DR2: ESA/Gaia/DPAC. Constellation figures based on those developed for the IAU by Alan MacRobert of Sky and Telescope magazine (Roger Sinnott and Rick Fienberg). NASA's page (opens in a new tab).
The map is a composite of 1.7 billion catalogued stars, not a photograph from one place: it shows stars far too faint for the eye, and no weather, Moon or city light. It is drawn here in this chart's projection, with each star where it was in 2000; the fastest-moving bright star has shifted about a minute of arc since, far less than a pixel here.
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
Rigel is a hot blue-white supergiant shining with the light of tens of thousands of Suns.
Jim Kaler (opens in a new tab) describes Rigel as a class B8 supergiant with a surface near 11,500 kelvin and a radius about 74 times the Sun's, nearly the size of Mercury's orbit. Counting the ultraviolet light its hot surface gives out, it shines with the light of some 85,000 Suns.
Kaler (opens in a new tab) gives its distance as 860 light-years, from the second reduction of the Hipparcos data, and NASA's Orion page (opens in a new tab) agrees at about 860. That makes it farther than Betelgeuse yet intrinsically brighter, and usually the brightest star in Orion.
It is young: NASA estimates (opens in a new tab) about 8 million years, Kaler (opens in a new tab) only about 10 million. In ESA's list (opens in a new tab) of the brightest stars it comes seventh, just behind Capella.
Sources for this section Jim Kaler, Rigel, STARS (University of Illinois) (opens in a new tab); NASA Science, Discovering the Universe Through the Constellation Orion (opens in a new tab); ESA, Hipparcos: The 50 Brightest Stars (opens in a new tab)
Beta, but brighter
Rigel carries the second Greek letter yet usually outshines Betelgeuse, the alpha.
Greek letters usually run in order of brightness within a constellation, but Rigel, beta Orionis, is normally brighter than Betelgeuse, alpha Orionis. Kaler suggests (opens in a new tab) two explanations: variable Betelgeuse may have been near its brightest when the letters were given out, or Johann Bayer simply went by position.
The letter is joined to the Latin possessive of the constellation's name, so Rigel is beta Orionis, “the beta of Orion”; the IAU's own example (opens in a new tab) is Hamal, alpha Arietis, the alpha of Aries.
Sources for this section Jim Kaler, Rigel, STARS (University of Illinois) (opens in a new tab); International Astronomical Union, The Constellations (opens in a new tab)
A name from Arabic
“Rigel” is Arabic for “foot”: the foot of the figure the Arabs called al-jauza.
The name comes from rijl al-jauza, “the foot of al-jauza” (opens in a new tab), the Arabic name for the figure; Kaler glosses al-jauza as the “Central One”. In the Greek figure the star is the Hunter's left foot.
Rigel is the spelling in the IAU Catalog of Star Names (opens in a new tab). The IAU's Working Group on Star Names (opens in a new tab) has standardised the spellings of such traditional names since 2015, and names visible stars from historical and Indigenous traditions where the culture of origin allows.
Keep in mind Other peoples know the same star by other names and stories. How stars get their names.
Sources for this section Jim Kaler, Rigel, STARS (University of Illinois) (opens in a new tab); IAU Working Group on Star Names, IAU Catalog of Star Names (IAU-CSN) (opens in a new tab); IAU Division C Working Group on Star Names (opens in a new tab)
Not alone, and not finished
A faint companion hides in Rigel's glare, and Rigel itself is expected to end as a supernova.
A seventh-magnitude companion sits nine seconds of arc away (opens in a new tab), itself a double star, at least 2,500 astronomical units from Rigel and taking at least 25,000 years to orbit it. A star that faint is normally easy in a small telescope, but Rigel's brilliance nearly overwhelms it.
Stellar theory, as Kaler reports it (opens in a new tab), expects Rigel to swell into a red supergiant much like Betelgeuse and eventually to explode, and he estimates it would then look about as bright as a quarter Moon. He also notes the uncertainties: Rigel may be less massive than the usual figure of about 18 Suns, and may already have been a red giant once.
Sources for this section Jim Kaler, Rigel, STARS (University of Illinois) (opens in a new tab)
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.
Sources
- Astronomy Jim Kaler, Rigel, STARS (University of Illinois) (opens in a new tab) for its type, size, luminosity, distance, age, name, companions and future · checked 27 September 2026
- Astronomy NASA Science, Discovering the Universe Through the Constellation Orion (opens in a new tab) for its place in Orion, distance, age and brightness · checked 27 September 2026
- Astronomy ESA, Hipparcos: The 50 Brightest Stars (opens in a new tab) for its rank · checked 27 September 2026
- Astronomy International Astronomical Union, The Constellations (opens in a new tab) for how Greek-letter names are formed · checked 27 September 2026
- Astronomy IAU Working Group on Star Names, IAU Catalog of Star Names (IAU-CSN) (opens in a new tab) for the IAU spelling · checked 2 October 2026
- Astronomy IAU Division C Working Group on Star Names (opens in a new tab) for how the IAU standardises names · checked 27 September 2026
