# Wezen (Delta Canis Majoris)

Wezen (Delta Canis Majoris) is a star in the constellation Canis Major, magnitude 1.8.

**A yellow-white supergiant so powerful that, as close as Sirius, it would shine like a half Moon.**

If Wezen were as close to us as Sirius, it would shine as brightly as a half Moon. It is a supergiant [star](https://astropilot.space/glossary/star) 14 to 15 times the Sun’s mass, around 190 times its width and 35,000 times as luminous. Curiously, its surface temperature of about 5,800 K is almost the same as the Sun’s.

It is only about 12 million years old, yet it has already stopped fusing hydrogen in its core. Over the next 100,000 years it will swell into a red supergiant, forging heavier and heavier elements in its core, until an iron core collapses and it explodes as a supernova.

Its name comes from the Arabic al-wazn, ‘weight’. The writer Richard Hinckley Allen thought it alluded to the star’s struggle to rise above northern horizons; the astronomer Jim Kaler noted how well it suits so massive a star.

Wezen (Delta Canis Majoris) is 1,600 light-years away: the light we see from it set off around AD 430, 110 years before the Hagia Sophia was completed in Constantinople.

## Did you know?

- **A year-long day.** Turning at about 28 km/s at its vast equator, Wezen may take about a year to spin once.
- **The third virgin.** An Arabic catalogue calls Wezen Thalath al Adzari, ‘the third virgin’ — one of a group of stars in the Great Dog’s hindquarters known as the Virgins.
- **On Brazil’s flag.** Wezen appears on the flag of Brazil, where it stands for the state of Roraima.

A bright yellow-white star south-east of Sirius, at the northern corner of the triangle it forms with Adhara and Aludra in the Great Dog’s hindquarters. Binoculars show the open cluster NGC 2354 just to its east.

## When and where to see it

It is best placed in the evening sky around February, when it crosses the meridian at about 10 pm local time (around midnight in January). It can be seen from everywhere south of 64°N and never sets south of 64°S.

At its highest it stands 14° up from 50°N, 29° up from 35°N, 64° up from the equator, 81° up from 35°S.

## Facts

- Type: Star
- Constellation: Canis Major
- Designations: Delta Canis Majoris, δ CMa, 25 CMa, HR 2693, HD 54605, HIP 34444
- Magnitude: 1.8
- Position: RA 7h 8.4m, Dec −26° 24′ (J2000)
- Spectral type: F8Ia
- Colour: yellow (B−V 0.68)
- Distance: 1,600 light-years
- Discovered: Known since antiquity

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