# Leepwal (Zeta Centauri)

Leepwal (Zeta Centauri) is a star in the constellation Centaurus, magnitude 2.5.

**Two hot stars locked in an eight-day orbit — named in the Marshall Islands as a son of Capella.**

Every eight days or so, two hot [blue-white](https://astropilot.space/glossary/star-colour) stars whirl around each other in Zeta Centauri, too close for any telescope to split. Astronomers know the [pair](https://astropilot.space/glossary/double-star) from the spectrum alone, where each star’s lines shift back and forth as they swing towards and away from us.

The brighter star has nearly eight times the Sun’s mass and six times its width, and spins at least 235 kilometres per second at its equator. At about 40 million years old it is young by the Sun’s standards, yet already easing off the main sequence into a subgiant.

In the Marshall Islands it is Ļeepwal, the third of the ten sons of Lōktañūr — the star we call Capella. In 2024 the IAU adopted the name, spelled Leepwal.

Leepwal (Zeta Centauri) is 380 light-years away: the light we see from it set off around 1645, 35 years after Galileo first turned a telescope to the sky.

## Did you know?

- **A borrowed letter.** In Bayer’s atlas of 1603, “Zeta Centauri” was Acrux, then counted as part of the Centaur. Lacaille gave the letter to this star in his catalogue of 1756.
- **A name passed around.** It has also been called Alnair, from the Arabic for “the bright star of the body of the Centaur” — a name first used for Acrux and now officially given to Alpha Gruis.
- **The Arsenal.** Chinese astronomers made it the first star of Kù Lóu, the Arsenal, a group of ten stars in Centaurus.

A blue-white star of magnitude 2.5 in Centaurus, about 13 degrees almost due north of Hadar (Beta Centauri). Its two stars are far too close for any telescope to split, so simply enjoy its colour in binoculars.

## When and where to see it

It is best placed in the evening sky around May, when it crosses the meridian at about 10 pm local time (around midnight in April). It can be seen from everywhere south of 43°N and never sets south of 43°S.

At its highest it stands below the horizon from 50°N, 8° up from 35°N, 43° up from the equator, 78° up from 35°S.

## Facts

- Type: Star
- Constellation: Centaurus
- Designations: Zeta Centauri, ζ Cen, HR 5231, HD 121263, HIP 68002
- Magnitude: 2.5
- Position: RA 13h 55.5m, Dec −47° 17′ (J2000)
- Spectral type: B2.5IV
- Colour: blue-white (B−V -0.22)
- Distance: 380 light-years
- Discovered: Known since antiquity

Open AstroPilot to see when Leepwal (Zeta Centauri) is highest tonight from your location, how easy it is with your telescope or binoculars, and an eyepiece view. https://astropilot.space/object/leepwal