Regulus in the birth chart: the fixed star at the heart of Leo

Star data

sefstars catalogue, Swiss Ephemeris 2.10.03.

Regulus is the bright star at the heart of the Lion and one of the four royal stars of astrological tradition. Astrologers have long tied it to authority and public recognition. In the tropical zodiac it no longer stands in Leo: around 2012 precession carried it into Virgo, where it sits at the very beginning of the sign.

In the sky

Regulus belongs to the constellation Leo and lies almost on the ecliptic itself, less than half a degree from it. That small latitude has a practical side: the Moon regularly passes in front of Regulus and hides it for a while, an event called an occultation. Few bright stars sit this close to the Sun's path; the others the Moon covers in the same way are Aldebaran, Antares and Spica.

For chart work this means that a conjunction with Regulus by zodiacal degree is also a close meeting in the sky, which is not true of stars far from the ecliptic.

Regulus is about 79 light-years away. It is a hot blue-white star of roughly three and a half solar masses, and it spins remarkably fast: one turn takes about 16 hours, not far from the speed at which its equator would start to shed gas. The spin has flattened it, and interferometers have measured the result directly: the equatorial diameter is about a third larger than the polar one.

Regulus is not a single star either. A faint companion, most likely a white dwarf, circles it every 40 days, and a more distant pair of stars travels through space with it. One explanation for the fast spin is that the companion, before it became a white dwarf, passed mass and rotation over to Regulus.

Finding it from Ukraine

Regulus is a star of spring evenings. In March and April it stands high in the south after dark, and by early summer it sinks into the western twilight. The easiest guide is the Sickle, a hook of stars in the western part of Leo shaped like a reversed question mark; Regulus is the bright star at the bottom of the hook.

From the latitude of Kyiv it climbs to about 50° above the southern horizon at its highest, so it is easy to see from anywhere in the country. The Sun passes Regulus in late August, and for some weeks around that date the star is lost in its glare.

The name

Regulus is Latin for "little king". Ptolemy called the star Basiliskos, with the same meaning, Latin writers rendered it as Rex, and the diminutive Regulus is credited to Copernicus. The royal idea is older than the Greeks: in Babylonian astronomy the star was Sharru, "the king". The other old title, "the Lion's Heart", goes back to classical times, Kardia Leontos in Greek and Cor Leonis in Latin, and Arabic astronomers took it over as Qalb al-Asad. Regulus is the official name approved by the International Astronomical Union.

The constellation's story fits the same picture. Greek and Roman writers identified Leo with the Nemean lion killed by Heracles in his first labour, and Hyginus explains its place among the stars by saying it was considered the king of beasts.

Nature according to Ptolemy

In the first book of the Tetrabiblos Ptolemy gives the star on the Lion's heart the nature of Mars and Jupiter. Every later reading rests on this formula, so it helps to take the two parts apart.

Mars stands for drive, courage, the readiness to compete and to act first. Jupiter stands for scale, confidence, generosity and the sense of being entitled to a larger place. Together they describe ambition with a goal in view: the push of Mars aimed at standing and influence. This is why tradition connects Regulus with leadership and high position, and reads its Jupiter side, fairness and magnanimity, as a check on the Mars side.

After Ptolemy

Regulus kept its standing in Renaissance astrology. Cornelius Agrippa, in the second book of his Three Books of Occult Philosophy, gives a list of fifteen Behenian stars "according to Hermes", and Regulus is seventh in it, under its old title, the Heart of the Lion. The royal reputation reached English writing too: Wyllyam Salysbury, in 1552, says that some call the Lion's heart "the Royall Starre", because those born under it were thought to have a royal nativity. The line survives because the star-name historian Richard Hinckley Allen quoted it.

Conjunctions with planets and angles

Regulus is used by conjunction, with an orb of about 1°; tighter contacts count for more. Two typical cases show how tradition reads it:

• Regulus on the MC. The Midheaven is the angle of career and public life, so here the star's themes go straight into reputation: a wish to lead and visibility in one's field.
• Regulus with the Sun. The Sun already speaks about identity and the drive to be seen. Regulus adds the Mars and Jupiter colour: confidence and a taste for responsibility. The rest of the Sun's condition in the chart decides how much of this is visible.

Precession and the change of sign

Like every star, Regulus drifts slowly along the zodiac (precession), and in its case the drift crossed a sign boundary within living memory. It took some two thousand years to cross Leo, and around 2012 it passed into Virgo, where it will stay for a comparable stretch.

This creates a practical problem with older books. A text from the twentieth century places Regulus late in Leo, and a chart from that period may indeed have the star there. A chart from today has it at the start of Virgo. A position copied from an old table without correction is off by about 1.4° for every century since the table's epoch, which is already wider than the orb. For a given birth year it is better to take the star's position for that year.

The move into Virgo does not change the star's nature. The sign only says where Regulus stands now; its nature comes from Ptolemy, so the core reading stays the same.

In celebrity charts

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

• Bernard Arnault: Ascendant, orb 0°09′
• Neymar: MC, orb 0°20′
• Dua Lipa: Venus, orb 0°28′

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