Pollux in the birth chart: the brighter of the heavenly Twins

Star data

sefstars catalogue, Swiss Ephemeris 2.10.03.

Pollux is one of the two bright stars of the constellation Gemini, and the brighter of the pair. In the tropical zodiac, though, it no longer stands in Gemini: it sits near the end of Cancer. Ptolemy gives it the nature of Mars alone, which makes it one of the plainest stars to read.

In the sky

Pollux and its twin Castor stand close together and are easy to take as a pair. Pollux is the brighter twin even though Bayer gave it the second Greek letter: Bayer letters do not always follow brightness, and the Twins show it clearly.

The constellation is Gemini, the sign is Cancer: precession has pulled the two apart. Pollux lies a few degrees north of the ecliptic, far enough that the Moon does not pass in front of it in our era.

The Twins are a winter and spring sight. Pollux reaches its highest point at midnight in mid-January and stays in the evening sky until late spring; at around 50° north it climbs to almost 70° above the southern horizon. The two bright stars stand side by side to the upper left of Orion, and the more orange one of the pair is Pollux.

What kind of star it is

Pollux is an orange giant about 34 light-years away, 1.7 to 2 times the mass of the Sun depending on the estimate, and almost nine times its radius. It has already left the long, stable stage of its life that the Sun is still in and has swollen into a giant. It is nothing like a supergiant such as Rigel, though: in true luminosity it is a modest star, and what makes it bright in our sky is mainly its closeness. Placed as far away as Rigel, Pollux would be invisible to the naked eye.

In 2006 astronomers announced a planet around it, found from small, regular shifts in the star's spectrum: a gas giant of at least 2.3 to 2.9 Jupiter masses in different studies, circling Pollux in about 590 days. In December 2015 the International Astronomical Union gave the planet the name Thestias, after the grandfather of Pollux in Greek myth, through a public naming contest. Not everyone is convinced the planet is real, and some astronomers think the signal may come from the star itself.

The name

Pollux is one of the Dioscuri, the twin brothers of Greek myth, and Castor is the other. Pollux is the Latin form of the Greek Polydeukes, and Ovid calls him Pugil, the boxer, after his skill with his fists. Early Arab astronomers called the star "the second of the forearm", and later Arabic names call it "the head of the hindmost twin". In astrology the twin stars are read separately, each with its own position and nature, and this page deals only with Pollux.

The twins in myth

The brothers had different fathers. Pollux was the immortal son of Zeus, Castor the mortal son of Tyndareus. When Castor was killed, Pollux would not accept immortality without him. Pindar's tenth Nemean Ode has Zeus offer him a choice: to spend half his days beneath the earth and half in the golden halls of heaven, together with his brother. Ovid's Fasti gives Pollux's own words, asking Zeus to divide his place in heaven between the two. Hyginus's Astronomica reports that Zeus then set them among the stars, and that because Pollux shared his life with his brother, they are said to shine on alternate days.

The twins were also protectors at sea. The Homeric hymn to the Dioscuri calls them saviours of men and of swift ships when storms rage over the sea.

Nature by tradition

In the first book of the Tetrabiblos Ptolemy describes Pollux simply as like Mars. Many stars get a mix of two planets; Pollux, like Aldebaran, gets one, which leaves less room for interpretation. The overview explains how Ptolemy's comparisons are read.

A Martian star brings the themes of Mars to whatever it touches: courage, drive, competition, the urge to act first and think later. Mars is also the planet of conflict, and the tradition sees Pollux as double-edged. On one side it describes energy and boldness, on the other impatience and a quick temper. Which side wins out depends on the planet the star sits on and on the chart as a whole.

The reading is clearer with a contrast. Capella mixes Mars with Mercury, so its Mars works through the mind and speech. Sirius, in the middle of Cancer, is mostly Jupiter with a little Mars. Pollux has no second planet to soften or redirect the Martian tone.

Conjunctions with planets and angles

Pollux is read by conjunction within an orb of about 1°. Two examples show how the tradition applies a single-planet nature.

• Sun on Pollux. The Sun describes the core of the person and the will. A Martian star on it adds a competitive streak and a wish to prove oneself through action. Tradition reads the contact as boldness, an appetite for challenge and a habit of meeting resistance head on.
• Pollux on the Ascendant. On the Ascendant a star shapes the manner. Here it adds directness, a quick reaction and a readiness to step forward, sometimes before others have finished speaking.

A Sun already under heavy pressure from Mars by aspect will carry the star's tone more sharply than a Sun in calm contacts.

Precession and sign

Pollux moves through the zodiac by about 1.4° a century. Near the end of Cancer it still has several degrees before Leo, so it will stay in Cancer for several more centuries. For charts from the last century its position differs from today's by up to a degree and a half or a little more, wider than the orb itself, so the star is checked for the year of birth.

In celebrity charts

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

• Lionel Messi: Mars, orb 0°32′

Find fixed stars in your chart