Skip to content
AsteriaStar
Subgiant · Cygnus

33 Cygni

Knowledge graph33 CygHR 7740HD 192696HIP 99655

Scientific overview

33 Cygni is a subgiant in the constellation Cygnus (Cygni), lying about 159.26 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 typeA3IV-Vn
Luminosity classIV
Apparent magnitude4.28
Absolute magnitude0.84
Luminosity (Sun = 1)40.29
Colour index (B−V)0.114
Distance159.26 ly (48.83 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 2186410658887682432

Parallax21.359 ± 0.1279 masSIMBAD · measured
Distance46.8244 pcGaia · estimated
Proper motion (RA)61.754 mas/yrSIMBAD · measured
Proper motion (Dec)81.428 mas/yrSIMBAD · measured
Radial velocity-18 ± 4.1 km/sSIMBAD · measured
Spectral typeA3IV-VnSIMBAD · catalogued
Right ascension (ICRS)303.3 degSIMBAD · measured
Declination (ICRS)56.5677 degSIMBAD · 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 2186410658887682432 · 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 · 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 subgiant has begun to evolve off the main sequence, brightening and expanding as core hydrogen fusion ends.

Location in the sky

Constellation
Cygnus
Hemisphere
Northern
Best seen
Summer (N. evening sky)
RA / Dec
20.2233h / 56.5677°

Knowledge connections

  • In constellationCygnus

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.