Vega (Alpha Lyrae)
Coordinates, distance (25.04 ly), magnitude 0.03 photometric zero point, rapid oblate rotation, and observing guide for Vega in Lyra.
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) | 0.03 mag | ± 0.01 mag | Johnson UBV standard star (historical 0.00 mag zero-point anchor) | definitive | Hipparcos New Reduction Catalog |
| Trigonometric parallax | 130.23 mas | ± 0.36 mas | Hipparcos New Reduction astrometric solution (J2000.0) | definitive | Hipparcos New Reduction Catalog |
| Distance in light-years | 25.04 ly | ± 0.07 ly | Derived from parallax 130.23 ± 0.36 mas (7.679 ± 0.021 pc) | definitive | Hipparcos New Reduction Catalog |
| Stellar mass | 2.135 M☉ | ± 0.074 M☉ | CHARA optical interferometry + oblate rotating stellar evolution model | high-confidence | SIMBAD Astronomical Database (CDS) |
| Polar effective temperature | 10060 K | 7900 to 10060 K | CHARA interferometric gravity-darkening profile (poles ~10,060 K vs equator ~7,900 K) | high-confidence | SIMBAD Astronomical Database (CDS) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Vega (Alpha Lyrae Zero-Point Star) at RA 18h 36m 56.34s, Dec +38° 47′ 01.3″ within Lyra, 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
Vega (Alpha Lyrae) is the fifth-brightest star in the night sky and the second-brightest star in the Northern Celestial Hemisphere after Arcturus, located 7.68 ± 0.02 parsecs (25.04 light-years) from Earth in Lyra. In modern observational history, Vega was the first star after the Sun to be photographed (by Bond and Whipple at Harvard in 1850), the first to have its spectrum photographed (by Henry Draper in 1872), and the foundational standard star chosen by Johnson and Morgan in 1953 to define apparent magnitude 0.0 across all wavelength bands (the 'Vega magnitude system').
Optical interferometry with the CHARA Array revealed that Vega is rotating once every 12.5 hours, bulging its equatorial radius to 2.726 solar radii while its polar radius is only 2.362 solar radii. Because we view Vega nearly pole-on, von Zeipel gravity darkening makes the hot polar cap facing Earth far brighter than its bloated equator, boosting Vega's apparent brightness by nearly a factor of two compared to how it would look equator-on.
In 1983 the IRAS infrared satellite discovered an excess of far-infrared thermal radiation around Vega—the first dusty circumstellar debris disk ever detected around another main-sequence star, recently imaged at ultra-high resolution by JWST's NIRCam and MIRI.
Practical Visual Observing Guide
- Shining blue-white near the zenith on July and August evenings for mid-northern observers, Vega anchors the western corner of the Summer Triangle alongside Deneb and Altair.
- Use Vega as an instant visual zero-point reference (magnitude 0.03): stars brighter than Vega (Arcturus, Capella, Sirius) have negative magnitudes, while dimmer stars have positive magnitudes.
- Just 1.8° northeast of Vega sits the famous 'Double Double' (Epsilon Lyrae), easily spotted in the same binocular field.
Catalog Cross-Identifications & Aliases
Common Aliases: α Lyrae · HD 172167 · HIP 91262 · 3 Lyrae
| Catalog Authority | Identifier |
|---|---|
| HIP | HIP 91262 |
| HD | HD 172167 |
| SIMBAD | * alf Lyr |
| WIKIDATA | Q3427 |
Related Objects, Comparisons & Guides
Epsilon Lyrae (The Double Double Star)
Coordinates, Gaia DR3 distance (160 ly), 208″ wide pair and 2.3″/2.4″ tight sub-pairs, and telescope resolution test guide for Epsilon Lyrae.
Ring Nebula (Messier 57 in Lyra)
Coordinates, Gaia DR3 central star distance (787 pc), magnitude 8.8, and telescope observing guide for the Ring Nebula (M57) in Lyra.
Altair (Alpha Aquilae Rapid Rotator)
Coordinates, Hipparcos distance (16.73 ly), magnitude 0.76, 8.9-hour oblate spin imaged by CHARA, and observing guide for Altair in Aquila.
Arcturus (Alpha Bootis Red Giant)
Coordinates, Hipparcos distance (36.7 ly), magnitude −0.05, halo-stream kinematics, and observing guide for Arcturus in Boötes.
Northern Summer Milky Way Observing Tour
Summer observing guide from the Summer Triangle (Vega, Altair, Deneb) and Hercules Keystone down the Milky Way rift to the Sagittarius Galactic Center.
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.
Stellar Spectral Classification (OBAFGKM)
Reference guide to Morgan-Keenan (MK) stellar classification (O B A F G K M), luminosity classes (I–V, WD), color index (B-V), and the H-R diagram.
Astronomical Epochs (J2000, J2016) & Precession
Why celestial coordinates specify a reference epoch (J2000.0 vs Gaia J2016.0), how axial precession shifts RA/Dec over time, and how ICRS anchors astrometry.
Bright, Multiple & Variable Stars Catalog
Cross-reference catalog of solar-neighborhood and navigation stars across Bayer, Henry Draper (HD), Hipparcos (HIP), WDS, and Gaia DR3 designations.
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)
- IAU Working Group on Star Names (WGSN) (2026 IAU WGSN Bulletin): Mamajek, E., et al. (IAU WGSN) 2016–2026, IAU Catalog of Star Names — International Astronomical Union
- JWST / MAST Science Archive & Mission Documentation (Cycle 1–4 Public Releases (2022–2026)): Rigby, J., et al. 2023, PASP, 135, 048001 (The Science Performance of JWST as Characterized in Commissioning) — NASA / ESA / CSA / STScI