Rigel in the birth chart: the bright star at the foot of Orion

Star data

sefstars catalogue, Swiss Ephemeris 2.10.03.

Rigel is the bright star at the foot of Orion. Ptolemy gave the bright stars of Orion other than its shoulders the nature of Jupiter and Saturn, a far steadier combination than the Mars and Mercury of Betelgeuse. In the tropical zodiac Rigel stands in the middle of Gemini.

What kind of star it is

Rigel is a blue supergiant, roughly a hundred thousand times more luminous than the Sun or more. A spectroscopic analysis published in 2006 gave it a mass of about 21 Suns, and its measured angular diameter at the Hipparcos distance implies a radius of more than seventy solar radii. Its brightness wavers slightly: the star belongs to the Alpha Cygni variables, supergiants whose atmospheres pulsate unevenly. The changes are too small to notice without instruments.

The distance is less certain than for most bright stars. The Hipparcos satellite put Rigel at about 860 light-years, while the distance of the stellar group in Orion it is thought to belong to gives about 1,200, so neither figure is treated as final. Rigel is also not alone. About nine arcseconds from it lies a faint eighth-magnitude companion, which, as Allen already noted, is not easy to pick out in Rigel's glare even with a telescope.

None of this enters the astrological reading, which rests on Ptolemy's description. It does explain why Rigel is so bright at such a distance.

Rigel in the sky

In the zodiac Rigel has a close neighbour: Aldebaran stands in the first third of Gemini, about seven degrees before it. Their natures in Ptolemy differ sharply: Aldebaran is pure Mars, Rigel Jupiter and Saturn. With a tight orb a planet meets one of them, not both, so it is worth checking which.

Their latitudes differ as well. Aldebaran lies close to the ecliptic, while Rigel is far south of it, so the two look closer in a list of zodiac positions than they are in the actual sky. For a star this far from the ecliptic, parans are often the better test.

To find Rigel, look for Orion on a winter evening. The three stars of the belt sit in the middle of the figure; below them and to the right is a bright blue-white star, which is Rigel, while reddish Betelgeuse stands above and to the left. Rigel lies a little south of the celestial equator, so at around 50° north it never climbs high: at best about 31° above the southern horizon. It reaches its highest point at midnight in the first half of December, and in the evening sky it is best placed from December to March.

The name

Rigel comes from the Arabic for "foot". The full phrase was Rijl Jauzah al-Yusra, "the left leg of al-Jauza", al-Jauza being the Arabic name for the giant figure that Greek tradition saw as Orion. Only the first word survived into European use. Richard Hinckley Allen, in his Star Names and Their Meanings (1899), notes that the form Rigel first appears in a 1521 edition of the Alfonsine Tables, the astronomical tables of medieval Castile. In 2016 the International Astronomical Union confirmed Rigel as the star's official proper name.

Orion and the Scorpion

The best-known story about the constellation explains its place in the sky. In Aratus's Phaenomena Orion offends Artemis and is killed by a scorpion, and the poet adds that when the Scorpion rises in the east, Orion flees below the western horizon. Hyginus's Astronomica tells the same thing in plainer terms: the constellations were set so that Orion sets as the Scorpion rises. The sky still behaves this way. Orion and Scorpius, home of Antares, lie on opposite sides of the sky and are never seen high at the same time.

Nature by tradition

In the first book of the Tetrabiblos Ptolemy treats the stars on Orion's shoulders separately and describes the remaining bright stars of the constellation as like Jupiter and Saturn.

Jupiter stands for growth, law and generosity; Saturn for structure, duty and patience. Together they describe authority grounded in knowledge and discipline: long work toward a distant result, an interest in institutions, teaching and organised knowledge, a reputation earned slowly rather than won quickly. The heavier side of the same pairing is conservatism and a habit of putting rules above people.

Ptolemy gives the same formula, Saturn and Jupiter, to the stars of Perseus, among them Algol, yet their reputations in later tradition could hardly be further apart. The planetary formula is only the starting point: the image of the constellation and the star's brightness also shape how tradition reads a star.

Conjunctions with planets and angles

Tradition reads a star through tight conjunctions, usually within about 1°. Two examples:

• Rigel on the MC. The Midheaven is the angle of work and public standing, so the Jupiter and Saturn themes show in career: work built on expertise and method, an affinity for teaching, law or institutions, recognition that comes with time and accumulated results.
• Rigel with Saturn. The star repeats one of its own planets, so Saturn's discipline and patience are emphasised, while the Jupiter part of the formula gives them a purpose wider than duty. Tradition reads this conjunction as a capacity for sustained, serious effort. If Saturn is under strain from hard aspects, the heavier side of the pairing becomes more prominent.

Precession and sign

Rigel stands in the middle of Gemini and will stay in the sign for about nine more centuries. Star positions drift by about 1.4° a century through precession, so positions from older books are already more than a degree behind, which is enough to move a contact in or out of orb. The sign only says where the star is now; its nature comes from Ptolemy's Jupiter and Saturn.

In celebrity charts

Conjunctions within 1° to the planets from the Sun to Saturn and to the chart angles.

• Lionel Messi: Venus, orb 0°06′
• RM: Descendant, orb 0°25′
• Jannik Sinner: Ascendant, orb 0°30′

Find fixed stars in your chart