Wezen (Delta Canis Majoris)
Coordinates, distance (~1,600 ly), magnitude 1.83, 215 R☉ yellow-white supergiant radius, and observing guide for Wezen in Canis Major.
Provenance-Backed Scientific Measurements
Every measurement below preserves its unit, uncertainty interval, observational method, reference epoch, quality status, and primary catalog source. See Uncertainty & Provenance for how competing measurements are handled.
| Parameter | Value | Uncertainty | Method & Epoch | Quality Status | Source Archive |
|---|---|---|---|---|---|
| Apparent visual magnitude (V) | 1.83 mag | ± 0.01 mag | Johnson UBV photoelectric photometry | definitive | Hipparcos New Reduction Catalog |
| Trigonometric parallax | 2.03 mas | ± 0.38 mas | Hipparcos New Reduction astrometric solution (~492 ± 90 pc / 1,600 ly) (J2000.0) | model-dependent | Hipparcos New Reduction Catalog |
| Photospheric linear radius | 215 R☉ | ± 40 R☉ | Narrabri/VLTI angular diameter (3.60 ± 0.05 mas) scaled to ~492 pc | model-dependent | SIMBAD Astronomical Database (CDS) |
| Bolometric luminosity | 50000 L☉ | ± 15000 L☉ | F8 Ia spectrophotometry & distance modulus (M_V ≈ −6.87) | model-dependent | SIMBAD Astronomical Database (CDS) |
| Evolutionary stellar mass | 16.9 M☉ | ± 1.5 M☉ | Rotating core-helium-burning evolutionary tracks (~10–12 Myr age) | model-dependent | SIMBAD Astronomical Database (CDS) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Wezen (Delta Canis Majoris Yellow Supergiant) at RA 07h 08m 23.48s, Dec -26° 23′ 35.5″ within Canis Major, alongside peak meridian transit altitudes for 40°N and 30°S observers. Use the RA/Dec Coordinate Converter to compute exact culmination altitude for your latitude.
Astrophysical Context & Structure
Wezen (Delta Canis Majoris, from the Arabic al-Wazn meaning 'the Weight'—so named because the star seems heavy and slow to lift itself above the northern winter horizon) is the third-brightest star in Canis Major at apparent visual magnitude 1.83, situated 10° southeast of Sirius and 2.8° north-northeast of Adhara. Despite appearing eight times dimmer than Sirius in our sky, Wezen is an absolute monster lying ~492 parsecs (~1,600 light-years) away—nearly 190 times farther than Sirius!
Classified as an F8 Ia yellow-white supergiant with an effective temperature of 6,100 K (only slightly hotter than the Sun's 5,772 K), Wezen has an absolute visual magnitude of M_V = −6.87 and radiates roughly 50,000 times the Sun's luminosity. If Wezen were swapped into the position of Sirius just 8.6 light-years from Earth, it would blaze in our sky at apparent magnitude −11.2—as bright as the waxing quarter Moon and casting sharp shadows at midnight!
With a measured angular diameter of 3.60 milliarcseconds corresponding to ~215 solar radii (~1.0 AU in radius), Wezen's photosphere would engulf the orbit of Earth if placed at the center of our Solar System. Only ~10 to 12 million years old and weighing ~17 solar masses, Wezen has ceased core hydrogen fusion and is rapidly evolving toward a red supergiant phase and an eventual Type II core-collapse supernova.
Practical Visual Observing Guide
- Forms the apex of the southern hindquarters triangle of Canis Major alongside Adhara (ε CMa) and Aludra (η CMa), glowing with a rich, creamy golden-yellow color in binoculars.
- Look just 1.4° north of Wezen with binoculars or a rich-field telescope to spot NGC 2354, a 6.5-magnitude open star cluster.
- Only 35 arcminutes south of Wezen lies the giant red hypergiant VY Canis Majoris—making Wezen the direct naked-eye stepping stone for finding one of the largest known stars in the Milky Way.
Catalog Cross-Identifications & Aliases
Common Aliases: δ Canis Majoris · HD 54605 · HIP 34444 · 25 Canis Majoris
| Catalog Authority | Identifier |
|---|---|
| HIP | HIP 34444 |
| HD | HD 54605 |
| SIMBAD | * del CMa |
| WIKIDATA | Q13042 |
Related Objects, Comparisons & Guides
Sirius (Alpha Canis Majoris Binary)
Coordinates, Hipparcos parallax (379.21 mas, 8.60 ly), magnitude −1.46, Sirius B white dwarf orbit, and observing guide for Sirius.
Adhara (Epsilon Canis Majoris Extreme-UV Star)
Coordinates, Hipparcos distance (430 ly), magnitude 1.50, peak extreme-UV sky irradiance, 7.5″ companion, and observing guide for Adhara.
VY Canis Majoris (Extreme Red Hypergiant)
Coordinates, VLBA maser parallax distance (1.17 kpc), 1,420 R☉ hypergiant radius, asymmetric mass-loss arcs, and guide for VY Canis Majoris.
Apparent vs Absolute Magnitude Explained
Understand the logarithmic Pogson astronomical magnitude scale, apparent visual magnitude (m), absolute magnitude (M at 10 parsecs), and bolometric corrections.
Angular Size, Separation & Field of View
How angular diameter (degrees, arcminutes, arcseconds), spherical angular separation, and small-angle physical diameter relate to telescope field of view.
Scientific Sources & Dataset Provenance
- Hipparcos New Reduction Catalog (2007 New Reduction): van Leeuwen, F. 2007, A&A, 474, 653 (Validation of the new Hipparcos reduction) — ESA / van Leeuwen (2007)
- SIMBAD Astronomical Database (CDS) (2026-10 release): Wenger, M., et al. 2000, A&AS, 143, 9 (The SIMBAD astronomical database) — Centre de Données astronomiques de Strasbourg