# Imai (Delta Crucis)

Imai (Delta Crucis) is a star in the constellation Crux, magnitude 2.8.

**The Southern Cross’s faintest star — a river calendar for the Mursi people of Ethiopia.**

For the Mursi people of Ethiopia, this star is a calendar. When Imai stops appearing in the evening sky at dusk, the Omo River is said to rise high enough to flatten the imai grass along its banks, before subsiding again. The Mursi follow a series of southern stars to track the river’s floods, among them Mimosa, Hadar and Alpha Centauri. In 2018 the IAU adopted the name Imai.

It is a hot [blue-white](https://astropilot.space/glossary/star-colour) [star](https://astropilot.space/glossary/star), about 20,400 K at the surface and 8,100 times as luminous as the Sun. It spins fast — at least 210 kilometres per second — and is beginning to evolve away from the main sequence towards becoming a giant.

Imai belongs to the Lower Centaurus Crux, a group of massive stars that formed together 16 to 20 million years ago.

Imai (Delta Crucis) is 350 light-years away: the light we see from it set off around 1675, around the time Isaac Newton published his laws of motion and gravity.

## Did you know?

- **On five flags.** Imai flies on the flags of Australia, New Zealand, Samoa and Papua New Guinea as part of the Southern Cross. On Brazil’s flag it is one of 27 stars and stands for the state of Minas Gerais.
- **The pale one.** In Portuguese it is sometimes called Pálida, “the pale one” — a fair name for the faintest star of the Cross.
- **The Eagle-hawk.** The Aranda and Luritja people of Central Australia saw Imai, Gacrux and two stars of Centaurus as a four-sided figure, Iritjinga, “the Eagle-hawk”.

A blue-white star of magnitude 2.8, the faintest of the Southern Cross’s four bright stars, at the western end of its crossbar. Compare it with Mimosa at the other end; the fainter fifth star, Epsilon Crucis, sits between Imai and Acrux.

## When and where to see it

It is best placed in the evening sky around April, when it crosses the meridian at about 10 pm local time (around midnight in March). It can be seen from everywhere south of 31°N and never sets south of 31°S.

At its highest it stands below the horizon from 50°N, below the horizon from 35°N, 31° up from the equator, 66° up from 35°S.

## Facts

- Type: Star
- Constellation: Crux
- Designations: Delta Crucis, δ Cru, HR 4656, HD 106490, HIP 59747
- Magnitude: 2.8
- Position: RA 12h 15.1m, Dec −58° 45′ (J2000)
- Spectral type: B2IV
- Colour: blue-white (B−V -0.18)
- Distance: 350 light-years
- Discovered: Known since antiquity

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