Mu Cephei
Scientific overview
Mu Cephei is a red supergiant in the constellation Cepheus (Cephei).
Class M. Cool red stars. The most common type in the galaxy, ranging from red dwarfs to red giants. Such stars have surface temperatures around 2,400–3,700 K and appear red to the eye.
Physical properties
| Spectral type | M2Ia |
| Luminosity class | Ia |
| Apparent magnitude | 4.23 |
| Colour index (B−V) | 2.242 |
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 2202630001603369856 · elevated RUWE
| Parallax | 0.119 ± 0.2637 mas | SIMBAD · measured |
| Distance | 4495.9 pc | Gaia · estimated |
| Proper motion (RA) | 3.439 mas/yr | SIMBAD · measured |
| Proper motion (Dec) | -4.108 mas/yr | SIMBAD · measured |
| Radial velocity | 23 ± 0.58 km/s | SIMBAD · measured |
| Spectral type | M2-Ia | SIMBAD · catalogued |
| Right ascension (ICRS) | 325.9 deg | SIMBAD · measured |
| Declination (ICRS) | 58.78 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 2202630001603369856 · 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 · 2008A&A...485..303M · 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 · 2020yCat.1350....0G · direct catalogue measurement · retrieved 2026-07-11
- Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2020yCat.1350....0G · 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 constellationCepheus
Related stars in Cepheus
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.