Kaus Borealis
Lambda Sagittarii
Scientific overview
Kaus Borealis is a red supergiant in the constellation Sagittarius (Sagittarii), lying about 78.18 light-years from Earth.
Class K. Cooler orange stars. Long-lived and abundant; many are stable hosts for planets. Such stars have surface temperatures around 3,700–5,200 K and appear orange to the eye.
Physical properties
| Spectral type | K1IIIb |
| Luminosity class | Ib |
| Apparent magnitude | 2.82 |
| Absolute magnitude | 0.92 |
| Luminosity (Sun = 1) | 37.256 |
| Colour index (B−V) | 1.025 |
| Distance | 78.18 ly (23.97 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 4076915349846977664 · elevated RUWE
| Parallax | 42.9198 ± 0.2128 mas | SIMBAD · measured |
| Distance | 23.2831 pc | Gaia · estimated |
| Proper motion (RA) | -46.152 mas/yr | SIMBAD · measured |
| Proper motion (Dec) | -185.1 mas/yr | SIMBAD · measured |
| Radial velocity | -43.2 ± 0.8 km/s | SIMBAD · measured |
| Spectral type | K1IIIb | SIMBAD · catalogued |
| Right ascension (ICRS) | 277 deg | SIMBAD · measured |
| Declination (ICRS) | -25.4217 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 4076915349846977664 · 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 · 1989ApJS...71..245K · 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 red supergiant is a colossal, cool, luminous evolved star. The largest known stars are red supergiants, and many end as supernovae.
Location in the sky
Knowledge connections
- In constellationSagittarius
Related stars in Sagittarius
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.