Okab
Zeta Aquilae
Scientific overview
Okab is a main-sequence star in the constellation Aquila (Aquilae), lying about 83.03 light-years from Earth.
Class A. White stars with strong hydrogen lines. Many of the brightest stars in the sky are class A. Such stars have surface temperatures around 7,500–10,000 K and appear white to the eye.
Physical properties
| Spectral type | A0Vn |
| Luminosity class | V |
| Apparent magnitude | 2.99 |
| Absolute magnitude | 0.96 |
| Luminosity (Sun = 1) | 35.942 |
| Colour index (B−V) | 0.014 |
| Distance | 83.03 ly (25.46 pc) |
Values are real catalogue data; fields without a reliable value are omitted, never estimated.
Precision measurements
Astrometry and astrophysics from SIMBAD and Gaia DR3 · Gaia DR3 4314399312979641728 · elevated RUWE
| Parallax | 38.2329 ± 0.3492 mas | SIMBAD · measured |
| Distance | 26.1269 pc | Gaia · estimated |
| Proper motion (RA) | -6.575 mas/yr | SIMBAD · measured |
| Proper motion (Dec) | -95.909 mas/yr | SIMBAD · measured |
| Radial velocity | -25 ± 4 km/s | SIMBAD · measured |
| Spectral type | A0IV-Vnn | SIMBAD · catalogued |
| Right ascension (ICRS) | 286.4 deg | SIMBAD · measured |
| Declination (ICRS) | 13.8635 deg | SIMBAD · measured |
Full field-level provenance
- Parallax: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · plx_value · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11
- Distance: ESA Gaia astrometric survey · Gaia EDR3 · Bailer-Jones (2021) · external.gaiaedr3_distance · r_med_geo · row 4314399312979641728 · Bayesian estimate · retrieved 2026-07-11
- Proper motion (RA): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · pmra · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11
- Proper motion (Dec): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · pmdec · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11
- Radial velocity: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · rvz_radvel · 2006AstL...32..759G · direct catalogue measurement · retrieved 2026-07-11
- Spectral type: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · sp_type · 2003AJ....126.2048G · catalogue identifier/value · retrieved 2026-07-11
- Right ascension (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · ra · 2007A&A...474..653V · direct catalogue measurement · retrieved 2026-07-11
- Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2007A&A...474..653V · direct catalogue measurement · retrieved 2026-07-11
measured = direct catalogue value · estimated = Bayesian inference (Bailer-Jones distance) · modeled = model output (Gaia GSP-Phot). Fields a source did not provide are omitted, never invented.
Evolution
A main-sequence star fuses hydrogen into helium in its core. It will remain on the main sequence for most of its life before evolving into a giant.
Location in the sky
Knowledge connections
- In constellationAquila
Related stars in Aquila
Sources
The primary and reference sources this topic draws on.
- HYG DatabaseHYG Database (Hipparcos + Yale Bright Star + Gliese), by D. Nash / astronexus
Aggregated, openly-licensed star catalogue combining Hipparcos, the Yale Bright Star Catalogue, and the Gliese Catalogue of Nearby Stars.
- HipparcosESA Hipparcos space astrometry mission
High-precision parallax, magnitude, and position for ~118,000 stars.